HV blocking generator (high voltage power supply) for experiments - you can buy it on the Internet or make it yourself. To do this, we need not a lot of details and the ability to work with a soldering iron.
In order to collect it you need:
1. Horizontal scan transformer TVS-110L, TVS-110PTs15 from tube b/w and color TVs (any line)
2. 1 or 2 capacitors 16-50v - 2000-2200pF
3. 2 resistors 27Ω and 270-240Ω
4. 1-transistor 2T808A KT808 KT808A or similar in characteristics. + good heatsink for cooling
5. Wires
6. Soldering iron
7. Straight arms
And so we take the lineman, disassemble it carefully, leave the secondary high-voltage winding, consisting of many turns of thin wire, a ferrite core. We wind our windings with enameled copper wire on the second free side of the ferite core, having previously made a tube around the ferite from thick cardboard.
First: 5 turns approximately 1.5-1.7 mm in diameter
Second: 3 turns approximately 1.1mm in diameter
In general, the thickness and number of turns can be varied. What was at hand - from that and made.
Resistors and a pair of powerful bipolar n-p-n transistors, KT808a and 2t808a, were found in the pantry. He did not want to make a radiator - due to the large size of the transistor, although later experience showed that a large radiator is definitely needed.
To power all this, I chose a 12V transformer, you can also power it from a regular 12 volt 7A acc. from UPS. (to increase the output voltage, you can apply not 12 volts, but for example 40 volts, but here you already need to think about good cooling trance, and turns primary winding you can do not 5-3 but 7-5 for example).
If you are going to use a transformer, then you will need a diode bridge to rectify the current from AC to DC, the diode bridge can be found in the power supply from the computer, you can also find capacitors and resistors + wires there.
as a result, we get 9-10kV at the output.
I placed the whole structure in the case from the PSU. it turned out pretty compact.
So, we have an HV Blocking Generator which allows us to experiment and run the Tesla Transformer.
The circuit is assembled on a blocking generator. NPN transistor you can put any: KT805, KT809A. Line transformer TVS-110LA or TVS-110L6. There is also a multiplier. You can solder your multiplier according to the scheme, or you can put a ready-made UN9 / 27 multiplier. Supply voltage 12-30 volts. Consumption 80 - 300 mA.
List of radio components of the circuit:
27 ohm 2 W
220 - 240 Ohm 5-7W
VT KT809A 
Transformer TVS-110LA or TVS-110L6
The primary winding is completely removed from the ferrite core and another coil is wound on a cardboard frame with insulating electrical tape, the first and second coil to the coil through a layer of electrical tape.
Winding L1 is a feedback winding and is wound with a wire of small diameter, it can be anything, for example, 0.2-0.3 mm. The number of turns of the coupling winding can be selected, but should be no more than 5 turns, because with a larger number, there is a risk of burning the transistor due to the relatively large induced voltage on the communication winding.
The winding L2 is working and is usually made with a thick wire (0.5-1.5 mm). The number of turns - the smaller, the greater the output voltage. But with fewer turns of this winding, there is a risk of burning the transistor. The optimal amount is 3-4 turns. These windings are located on the core and must be reliably isolated from it, because. in case of breakdown from the secondary to the core and hit high voltage high frequency on any of the windings, you can kill the transistor with a 99% guarantee.
Low-power high-voltage generators are widely used in flaw detection, for powering portable particle accelerators, X-ray and cathode-ray tubes, photomultipliers, and ionizing radiation detectors. In addition, they are also used for electropulse destruction of solids, obtaining ultrafine powders, synthesis of new materials, as spark leak detectors, for launching gas-discharge light sources, for electric-discharge diagnostics of materials and products, for obtaining gas-discharge photographs by the method of S. D. Kirlian , testing the quality of high-voltage insulation. In everyday life, similar devices are used as power sources for electronic traps of ultrafine and radioactive dust, electronic ignition systems, for electro-fluvial chandeliers (chandeliers by A. L. Chizhevsky), air ionizers, medical devices, gas lighters, electric fences, electric shockers etc. .
Conventionally, high voltage generators include devices that generate voltages above 1 kV.
The generator of high-voltage pulses using a resonant transformer (Fig. 11.1) is made according to the classical scheme on a gas discharger RB-3.
Capacitor C2 is charged by a pulsating voltage through diode VD1 and resistor R1 to the breakdown voltage of the gas discharger. As a result of the breakdown of the gas gap of the arrester, the capacitor is discharged onto the primary winding of the transformer, after which the process is repeated. As a result, damped high-voltage pulses with an amplitude of up to 3 ... 20 kV are formed at the output of transformer T1.
To protect the output winding of the transformer from overvoltage, a surge arrester is connected in parallel to it, made in the form of electrodes with an adjustable air gap.
Rice. 11.1. Scheme of a high-voltage pulse generator using a gas discharger
Rice. 11.2. Scheme of a high-voltage pulse generator with voltage doubling
Transformer T1 of the pulse generator (Fig. 11.1) is made on an open ferrite core M400NN-3 with a diameter of 8 and a length of 100 mm. The primary (low-voltage) winding of the transformer contains 20 turns of wire MGSHV 0.75 mm with a winding pitch of 5 ... 6 mm. The secondary winding contains 2400 turns of ordinary winding of wire PEV-2 0.04 mm. The primary winding is wound over the secondary winding through a polytetrafluoroethylene (fluoroplastic) gasket 2 × 0.05 mm. The secondary winding of the transformer must be reliably isolated from the primary.
A version of the generator of high-voltage pulses using a resonant transformer is shown in fig. 11.2. In this generator circuit there is a galvanic isolation from the mains. Mains voltage enters the intermediate (step-up) transformer T1. The voltage removed from the secondary winding of the network transformer is supplied to the rectifier, which operates according to the voltage doubling scheme.
as a result of the operation of such a rectifier, a positive voltage appears on the upper plate of the capacitor C2 relative to the neutral wire, equal to V2L / „, where is the voltage on the secondary winding of the power transformer.
A corresponding voltage of the opposite sign is formed on the capacitor C1. As a result, the voltage on the plates of the capacitor C3 will be equal to 2 V2L / „.
The charge rate of capacitors C1 and C2 (C1=C2) is determined by the resistance value R1.
When the voltage on the plates of the capacitor C3 equals the breakdown voltage of the gas discharger FV1, a breakdown of its gas gap will occur, the capacitor C3 and, accordingly, the capacitors C1 and C2 will be discharged, periodic damped oscillations will occur in the secondary winding of the transformer T2. After the capacitors are discharged and the arrester is turned off, the process of charging and subsequent discharge of the capacitors to the primary winding of the transformer T2 will be repeated again.
The high-voltage generator used to take photographs in a gas discharge, as well as to collect ultrafine and radioactive dust (Fig. 11.3) consists of a voltage doubler, relaxation generator pulses and step-up resonant transformer.
The voltage doubler is made on diodes VD1, VD2 and capacitors C1, C2. The charging circuit is formed by capacitors C1 - C3 and resistor R1. Parallel to the capacitors C1 - C3, a 350 V gas discharger is connected with the primary winding of the step-up transformer T1 connected in series.
As soon as the level of direct voltage on the capacitors C1 - C3 exceeds the breakdown voltage of the arrester, the capacitors will be discharged through the winding of the step-up transformer and as a result a high-voltage pulse is formed. The circuit elements are chosen so that the frequency of pulse formation is about 1 Hz. Capacitor C4 is designed to protect the output terminal of the device from the ingress of mains voltage.
Output voltage device is entirely determined by the properties of the transformer used and can reach 15 kV. high voltage output transformer
Rice. 11.3. Scheme of a high voltage pulse generator using a gas spark gap or dinistors
a voltage of the order of ^0 kV is made on a dielectric tube with an outer diameter of 8 and a length of 150 mm, a copper electrode with a diameter of 1.5 mm is located inside. The secondary winding contains 3 ... 4 thousand turns of PELSHO 0.12 wire, wound turn to turn in 10 ... 13 layers (winding width 70 mm) and impregnated with YF-2 glue with polytetrafluoroethylene interlayer insulation. The primary winding contains 20 turns of PEV 0.75 wire passed through a PVC cambric.
As such a transformer, you can also use a modified horizontal TV output transformer; transformers for electronic lighters, flash lamps, ignition coils, etc.
The R-350 gas discharger can be replaced by a switchable chain of KN102 type dinistors (Fig. 11.3, right), which will allow you to step change the output voltage. To evenly distribute the voltage across the dinistors, resistors of the same rating with a resistance of 300 ... 510 kOhm are connected in parallel to each of them.
A variant of the circuit of a high-voltage generator using a gas-filled device, a thyratron, as a threshold-switching element is shown in fig. 11.4.
The mains voltage is rectified by the diode VD1. The rectified voltage is smoothed by the capacitor C1 and supplied to the charging circuit R1, C2. As soon as the voltage on the capacitor C2 reaches the ignition voltage of the thyratron VL1, it
Rice. 11.4. Scheme of a high voltage pulse generator using a thyratron
flashes. Capacitor C2 is discharged through the primary winding of transformer T1, the thyratron goes out, the capacitor starts charging again, etc.
An automobile ignition coil was used as a transformer T1.
Instead of the thyratron VL1 MTX-90, one or more dinistors of the KN102 type can be included. The amplitude of the load voltage can be adjusted by the number of included dinistors.
The design of a VU converter using a thyratron switch is described in . Note that other types of gas-filled devices can also be used to discharge the capacitor.
More promising is the use of semiconductor switching devices in modern high-voltage generators. Their advantages are clearly expressed: they are high repeatability of parameters, lower cost and dimensions, high reliability.
Below we will consider generators of high-voltage pulses using semiconductor switching devices (dinistors, thyristors, bipolar and field-effect transistors).
Quite equivalent, but low-current analogue of gas dischargers are dinistors.
On fig. 11.5 shows the electrical circuit of a generator made on dinistors. In its structure, the generator is completely similar to those described earlier (Fig. 11.1, 11.4). The main difference lies in the replacement of the gas discharger with a chain of series-connected dinistors.
Rice. 11.5. Scheme of a high-voltage pulse generator on dinistors
Rice. 11.6. Scheme of a high-voltage pulse generator with a bridge rectifier
It should be noted that the efficiency of such an analogue and switching currents is noticeably lower than that of the prototype, however, dinistors are more affordable and more durable.
A somewhat complicated version of the high-voltage pulse generator is shown in Fig. 11.6. The mains voltage is supplied to the bridge rectifier diodes VD1 - VD4. The rectified voltage is smoothed by capacitor C1. A constant voltage of about 300 V is formed on this capacitor, which is used to power a relaxation oscillator made up of elements R3, C2, VD5 and VD6. Its load is the primary winding of the transformer T1. Pulses with an amplitude of approximately 5 kBv are taken from the secondary winding, with a repetition rate of up to 800 Hz.
The chain of dinistors must be designed for a turn-on voltage of about 200 V. Here you can use dinistors of the type KN102 or D228. In this case, it should be borne in mind that the turn-on voltage of dinistors of the KN102A, D228A type is 20 V; KN102B, D228B - 28 V; KN102V, D228V - 40 V;
KN102G, D228G - 56 V; KN102D, D228D - 80 V; KN102E - 75 V; KN102Zh, D228Zh - 120 V; KN102I, D228I - 150 B.
As a transformer T1 in the above devices, a modified horizontal transformer from a black and white TV can be used. Its high-voltage winding is left, the rest is removed and a low-voltage (primary) winding is wound instead of them - 15 ... 30 turns of PEV wire with a diameter of 0.5 ... 0.8 mm.
When choosing the number of turns of the primary winding, the number of turns of the secondary winding should be taken into account. It must also be borne in mind that the magnitude of the output voltage of the high-voltage pulse generator depends to a greater extent on the tuning of the transformer circuits to resonance, rather than on the ratio of the number of turns of the windings.
The characteristics of some types of horizontal television transformers are shown in table 11.1.
Table 11.1. Parameters of high-voltage windings of unified horizontal-scan television transformers
|
Transformer type |
Number of turns |
R windings, Ohm |
||||
|
TVS-A, TVS-B |
||||||
|
TVS-110, TVS-110M |
||||||
|
Transformer type |
Number of turns |
R windings, Oi |
||||
|
TVS-90LTs2, TVS-90LTs2-1 |
||||||
|
TVS-110PTs15 |
||||||
|
TVS-110PTs16, TVS-11RPTs18 |
||||||
Rice. 11.7. Wiring diagram high voltage pulse generator
On fig. 11.7 shows a diagram of a two-stage high-voltage pulse generator published on one of the sites, in which a thyristor is used as a switching element. In turn, as a threshold element that determines the repetition rate of high-voltage pulses and triggers the thyristor, gas discharge device- neon lamp (chain HL1, HL2).
When the supply voltage is applied, the pulse generator, made on the basis of the VT1 transistor (2N2219A - KT630G), generates a voltage of about 150 V. This voltage is rectified by the VD1 diode and charges the capacitor C2.
After the voltage across capacitor C2 exceeds the ignition voltage neon lamps HL1, HL2, through the current-limiting resistor R2, the capacitor will be discharged to the control electrode of the thyristor VS1, the thyristor will open. The discharge current of the capacitor C2 will create electrical oscillations in the primary winding of the transformer 12.
The thyristor turn-on voltage can be adjusted by selecting neon lamps with different ignition voltages. You can stepwise change the thyristor turn-on voltage by switching the number of neon lamps connected in series (or dinistors replacing them).
Rice. 11.8. Diagram of electrical processes on the electrodes of semiconductor devices (to Fig. 11.7)
The voltage diagram at the base of the transistor VT1 and at the anode of the thyristor is shown in fig. 11.8. As follows from the presented diagrams, the blocking oscillator pulses have a duration of approximately 8 ms. The charge of the capacitor C2 occurs stepwise-exponentially in accordance with the action of pulses taken from the secondary winding of the transformer T1.
At the output of the generator, pulses with a voltage of approximately 4.5 kV are formed. As a transformer T1, an output transformer for low-frequency amplifiers was used. As a high-voltage transformer T2, a transformer from a flashlight or a recycled (see above) horizontal scanning television transformer was used.
A diagram of another version of the generator using a neon lamp as a threshold element is shown in fig. 11.9.
Rice. 11.9. The electrical circuit of the generator with a threshold element on a neon lamp
The relaxation generator in it is made on the elements R1, VD1, C1, HL1, VS1. It works with positive half-cycles of the mains voltage, when the capacitor 01 is charged to the turn-on voltage of the threshold element on the neon lamp HL1 and the thyristor VS1. The VD2 diode dampens the self-induction pulses of the primary winding of the step-up transformer T1 and allows you to change the output voltage of the generator. The output voltage reaches 9 kV. The neon lamp is also a signaling device for connecting the device to the network.
The high-voltage transformer is wound on a segment of a rod with a diameter of 8 and a length of 60 mm made of M400NN ferrite. First, the primary winding is placed - 30 turns of PELSHO 0.38 wire, and then the secondary - 5500 turns of PELSHO 0.05 or larger diameter. Between the windings and every 800 ... 1000 turns of the secondary winding, an insulation layer is laid from a polyvinyl chloride insulating tape.
In the generator, it is possible to introduce a discrete multi-stage adjustment of the output voltage by switching in a series circuit of neon lamps or dinistors (Fig. 11.10). In the first variant, two steps of regulation are provided, in the second - up to ten or more (when using KN102A dinistors with a switching voltage of 20 V).
Rice. 11.10. Electrical circuit of the threshold element
Rice. 11.11. The electrical circuit of the high voltage generator with a threshold element on the diode
A simple high voltage generator (Fig. 11.11) allows you to get pulses with an amplitude of up to 10 at the output.
Switching of the control element of the device occurs at a frequency of 50 Hz (on one half-wave of the mains voltage). Diode VD1 (D219A (Sch220, D223)), operating under reverse bias in the avalanche breakdown mode, was used as a threshold element.
When the avalanche breakdown voltage is exceeded at the semiconductor junction of the diode, the diode transitions to the conducting state. The voltage from the charged capacitor C2 is applied to the control electrode of the thyristor VS1. After turning on the thyristor, the capacitor C2 is discharged onto the winding of the transformer T1.
Transformer T1 has no core. It is made on a coil with a diameter of 8 mm from polymethyl methacrylate or polytetrachlorethylene and contains three spaced sections 9 mm wide. The step-up winding contains 3×1000 turns wound with PET wire, PEV-2 0.12 mm. After winding, the winding must be impregnated with paraffin. 2 - 3 layers of insulation are applied over the paraffin, after which the primary winding is wound - 3 × 10 turns of PEV-2 wire 0.45 mm.
Thyristor VS1 can be replaced by another for a voltage above 150 V. The avalanche diode can be replaced by a chain of dinistors (Fig. 11.10, 11.11 below).
Scheme of a low-power portable source of high voltage pulses with self-powered from one galvanic cell (Fig. 11.12) consists of two generators. The first is built on two low-power transistors, the second - on a thyristor and a dinistor.
Rice. 11.12. Scheme of a voltage generator with a low-voltage supply and a thyristor-dinistor key element
The cascade on transistors of different conductivity converts low-voltage direct voltage into high-voltage pulsed voltage. The timing chain in this generator is the elements C1 and R1. When the power is turned on, the transistor VT1 opens, and the voltage drop across its collector opens the transistor VT2. Capacitor C1, charging through resistor R1, reduces the base current of transistor VT2 so much that transistor VT1 goes out of saturation, and this leads to closing of VT2. The transistors will be closed until the capacitor C1 is discharged through the primary winding of the transformer T1.
The increased pulse voltage taken from the secondary winding of the transformer T1 is rectified by the diode VD1 and fed to the capacitor C2 of the second generator with a thyristor VS1 and a dinistor VD2. In each positive half-cycle, the storage capacitor C2 is charged to the amplitude value of the voltage equal to the switching voltage of the dynistor VD2, i.e. up to 56 V (nominal pulse triggering voltage for dinistor type KN102G).
The transition of the dinistor to the open state affects the control circuit of the thyristor VS1, which in turn also opens. Capacitor C2 is discharged through the thyristor and the primary winding of transformer T2, after which the dinistor and thyristor close again and the next charge of the capacitor begins - the switching cycle is repeated.
Pulses with an amplitude of several kilovolts are taken from the secondary winding of the transformer T2. The frequency of spark discharges is approximately 20 Hz, but it is much less than the frequency of pulses taken from the secondary winding of the transformer T1. This happens because the capacitor C2 is charged to the switching voltage of the dinistor not in one, but in several positive half-cycles. The capacitance value of this capacitor determines the power and duration of the output discharge pulses. The average value of the discharge current, which is safe for the dinistor and the control electrode of the trinistor, is chosen based on the capacitance of this capacitor and the magnitude of the pulse voltage supplying the cascade. To do this, the capacitance of the capacitor C2 should be approximately 1 uF.
Transformer T1 is made on an annular ferrite magnetic circuit of the K10x6x5 type. It has 540 turns of PEV-2 0.1 wire with a grounded outlet after the 20th turn. The beginning of its winding is connected to the transistor VT2, the end - to the diode VD1. The T2 transformer is wound on a coil with a ferrite or permalloy core with a diameter of 10 mm and a length of 30 mm. A coil with an outer diameter of 30 mm and a width of 10 mm is wound with a PEV-2 wire of 0.1 mm until the frame is completely filled. Before the end of the winding, a grounded tap is made, and the last row of wire of 30 ... 40 turns is wound round to round over the insulating layer of varnished fabric.
Transformer T2 in the course of winding must be impregnated with insulating varnish or BF-2 glue, then dried thoroughly.
Instead of VT1 and VT2, you can use any low-power transistors that can operate in a pulsed mode. Thyristor KU101E can be replaced with KU101G. Power source - galvanic cells with a voltage of not more than 1.5 V, for example, 312, 314, 316, 326, 336, 343, 373, or disk nickel-cad-miview batteries of the type D-0.26D, D-0.55S etc.
The thyristor generator of high-voltage pulses with mains supply is shown in fig. 11.13.
Rice. 11.13. Electric circuit of a high-voltage pulse generator with a capacitive energy storage and a thyristor switch
During the positive half-cycle of the mains voltage, the capacitor C1 is charged through the resistor R1, the diode VD1 and the primary winding of the transformer T1. The thyristor VS1 is closed at the same time, since there is no current through its control electrode (the voltage drop across the VD2 diode in the forward direction is small compared to the voltage required to open the thyristor).
With a negative half-cycle, the diodes VD1 and VD2 close. A voltage drop is formed on the thyristor cathode relative to the control electrode (minus - on the cathode, plus - on the control electrode), a current appears in the control electrode circuit, and the thyristor opens. At this moment, the capacitor C1 is discharged through the primary winding of the transformer. A load voltage pulse appears in the secondary winding. And so - every period of mains voltage.
At the output of the device, bipolar pulses of high voltage are formed (since damped oscillations occur when the capacitor is discharged in the primary winding circuit).
Resistor R1 can be made up of three MLT-2 resistors connected in parallel with a resistance of 3 kOhm.
Diodes VD1 and VD2 must be rated for a current of at least 300 mA and a reverse voltage of at least 400 V (VD1) and 100 B (VD2). Capacitor C1 of the MBM type for a voltage of at least 400 B. Its capacitance - a fraction of a microfarad - is selected experimentally. Thyristor VS1 type KU201K, KU201L, KU202K - KU202N. Transformer T1 - ignition coil B2B (6 B) from a motorcycle or car.
The TVS-110L6, TVS-110LA, TVS-110AM horizontal scanning transformer can be used in the device.
A fairly typical circuit of a high-voltage pulse generator with a capacitive energy storage is shown in fig. 11.14.
Rice. 11.14. Scheme of a thyristor generator of high-voltage pulses with a capacitive energy storage
The generator contains a quenching capacitor C1, a diode rectifier bridge VD1 - VD4, a thyristor switch VS1 and a control circuit. When the device is turned on, capacitors C2 and C3 are charged, the thyristor VS1 is still closed and does not conduct current. The voltage limit on the capacitor C2 is limited by the zener diode VD5 to 9 B. In the process of charging the capacitor C2 through the resistor R2, the voltage on the potentiometer R3 and, accordingly, on the control transition of the thyristor VS1 increases to a certain value, after which the thyristor switches to a conducting state, and the capacitor C3 through thyristor VS1 is discharged through the primary (low-voltage) winding of transformer T1, generating a high-voltage pulse. After that, the thyristor closes and the process starts again. Potentiometer R3 sets the thyristor threshold VS1.
The pulse repetition frequency is 100 Hz. An automobile ignition coil can be used as a high-voltage transformer. In this case, the output voltage of the device will reach 30...35 kV. The thyristor high-voltage pulse generator (Fig. 11.15) is controlled by voltage pulses taken from a relaxation generator made on a VD1 dinistor. The operating frequency of the control pulse generator (15 ... 25 Hz) is determined by the value of the resistance R2 and the capacitance of the capacitor C1.
Rice. 11.15. The electrical circuit of the thyristor generator of high-voltage pulses with pulse control
The relaxation generator is connected to the thyristor switch through pulse transformer T1 type MIT-4. As the output transformer T2, a high-frequency transformer from the Iskra-2 darsonvalization apparatus is used. The output voltage of the device can reach up to 20 ... 25 kV.
On fig. 11.16 shows the option of supplying control pulses to the thyristor VS1.
The voltage converter (Fig. 11.17), developed in Bulgaria, contains two stages. In the first of them, the load of the key element, made on the transistor VT1, is the winding of the transformer T1. Control pulses of a rectangular shape periodically turn on / off the key on the transistor VT1, thereby connecting / disconnecting the primary winding of the transformer.
Rice. 11.16. Thyristor switch control option
Rice. 11.17. Electrical diagram of a two-stage high-voltage pulse generator
In the secondary winding, an increased voltage is induced, proportional to the transformation ratio. This voltage is rectified by the diode VD1 and charges the capacitor C2, which is connected to the primary (low-voltage) winding of the high-voltage transformer T2 and the thyristor VS1. The operation of the thyristor is controlled by voltage pulses taken from the additional winding of the transformer T1 through a chain of elements that correct the shape of the pulse.
As a result, the thyristor periodically turns on / off. Capacitor C2 is discharged to the primary winding of the high-voltage transformer.
High voltage pulse generator, fig. 11.18, contains a single-junction transistor generator as a control element.
The mains voltage is rectified by a diode bridge VD1 - VD4. Ripple rectified voltage smoothes
Rice. 11.18. Scheme of a high-voltage pulse generator with a control element on a unijunction transistor
capacitor C1, the current of the capacitor charge at the moment the device is connected to the network is limited by the resistor R1. Capacitor C3 is charged through resistor R4. At the same time, a pulse generator on a unijunction transistor VT1 comes into action. Its "trigger" capacitor C2 is charged through resistors R3 and R6 from a parametric stabilizer (ballast resistor R2 and zener diodes VD5, VD6). As soon as the voltage on the capacitor 02 reaches a certain value, the transistor VT1 switches, and an opening pulse is sent to the control transition of the thyristor VS1.
Capacitor 03 is discharged through the thyristor VS1 to the primary winding of the transformer T1. A load voltage pulse is formed on its secondary winding. The repetition rate of these pulses is determined by the frequency of the generator, which, in turn, depends on the parameters of the chain R3, R6 and 02. With a tuning resistor R6, you can change the output voltage of the generator by about 1.5 times. In this case, the pulse frequency is regulated within 250 ... 1000 Hz. In addition, the output voltage changes when the resistor R4 is selected (in the range from 5 to 30 kOhm.
It is desirable to use capacitors with paper (01 and 03 - on Rated voltage not less than 400 V); the diode bridge must be designed for the same voltage. Instead of what is indicated on the diagram, you can use the thyristor T10-50 or, in extreme cases, KU202N. Zener diodes VD5, VD6 should provide a total stabilization voltage of about 18 B.
The transformer is made on the basis of TVS-110P2 from black and white TVs. All primary windings are removed and 70 turns of PEL or PEV wire with a diameter of 0.5 ... 0.8 mm are wound onto the vacated space.
Electrical circuit of the high voltage pulse generator, fig. 11.19, consists of a diode-capacitor voltage multiplier (diodes VD1, VD2, capacitors C1 - C4). Its output is a constant voltage of approximately 600 V.
Rice. 11.19. Scheme of a high-voltage pulse generator with a mains voltage doubler and a trigger pulse generator on a unijunction transistor
A single-junction transistor VT1 of the KT117A type was used as the threshold element of the device. The voltage at one of its bases is stabilized by a parametric stabilizer on a VD3 zener diode of the KS515A type (stabilization voltage 15 B). Capacitor C5 is charged through resistor R4, and when the voltage at the control electrode of transistor VT1 exceeds the voltage at its base, VT1 will switch to a conducting state, and capacitor C5 will be discharged to the control electrode of thyristor VS1.
When the thyristor is turned on, a chain of capacitors C1 - C4, charged to a voltage of about 600 ... 620 B, is discharged to the low-voltage winding of the step-up transformer T1. After that, the thyristor is turned off, the charge-discharge processes are repeated at a frequency determined by the constant R4C5. Resistor R2 limits the short circuit current when the thyristor is turned on and at the same time is an element of the charging circuit of capacitors C1 - C4.
The converter circuit (Fig. 11.20) and its simplified version (Fig. 11.21) is divided into the following nodes: network surge filter (noise filter); electronic regulator; high voltage transformer.
Rice. 11.20. Electrical diagram of a high voltage generator with a mains filter
Rice. 11.21. Electrical diagram of a high voltage generator with a mains filter
The scheme in fig. 11.20 works as follows. Capacitor SZ is charged through a diode rectifier VD1 and resistor R2 to the peak value of the mains voltage (310 B). This voltage enters through the primary winding of the transformer T1 to the anode of the thyristor VS1. On the other branch (R1, VD2 and C2), capacitor C2 is slowly charged. When the breakdown voltage of the VD4 dinistor is reached during its charging (within 25 ... 35 B), the capacitor C2 is discharged through the control electrode of the thyristor VS1 and opens it.
Capacitor C3 is almost instantly discharged through an open thyristor VS1 and the primary winding of the transformer
T1. The pulsed alternating current induces a high voltage in the secondary winding T1, the magnitude of which can exceed 10 kV. After the discharge of the capacitor C3, the thyristor VS1 closes, and the process is repeated.
A television transformer is used as a high-voltage transformer, in which the primary winding is removed. For the new primary winding, a winding wire with a diameter of 0.8 mm is used. The number of turns is 25.
For the manufacture of inductors of the barrier filter L1, L2, high-frequency ferrite cores are best suited, for example, 600НН with a diameter of 8 mm and a length of 20 mm, having approximately 20 turns of a winding wire with a diameter of 0.6 ... 0.8 mm.
Rice. 11.22. Electric circuit of a two-stage high voltage generator with a control element on a field-effect transistor
A two-stage load voltage generator (author - Andres Estaban de la Plaza) contains a transformer pulse generator, a rectifier, a timing RC circuit, a key element on a thyristor (triac), a high-voltage resonant transformer and a thyristor operation control circuit (Fig. 11.22).
Analog transistor TIP41 - KT819A.
Low voltage transformer voltage converter with crossover feedback, assembled on transistors VT1 and VT2, generates pulses with a repetition rate of 850 Hz. Transistors VT1 and VT2 are mounted on radiators made of copper or aluminum to facilitate operation when high currents flow.
The output voltage taken from the secondary winding of the transformer T1 of the low-voltage converter is rectified by the diode bridge VD1 - VD4 and charges the capacitors C3 and C4 through the resistor R5.
The thyristor turn-on threshold is controlled by a voltage regulator, which includes a field-effect transistor VT3.
Further, the operation of the converter does not differ significantly from the processes described earlier: there is a periodic charge / discharge of capacitors to the low-voltage winding of the transformer, and damped electrical oscillations are generated. The output voltage of the converter when used at the output as a step-up transformer of the ignition coil from the car, reaches 40 ... 60 kV at resonant frequency about 5 kHz.
Transformer T1 (output flyback transformer) contains 2 × 50 turns of wire with a diameter of 1.0 mm, wound bifilar. The secondary winding contains 1000 turns with a diameter of 0.20 ... 0.32 mm.
Note that modern bipolar and field-effect transistors can be used as controlled key elements.
The device in question generates electrical discharges with a voltage of about 30kV, so please be extremely careful during assembly, installation and further use. Even after the circuit is turned off, a part of the voltage remains in the voltage multiplier.
Of course, this voltage is not fatal, but the included multiplier can be a danger to your life. Follow all safety precautions.
And now closer to the point. To obtain high-potential discharges, components from the horizontal scan of a Soviet TV set were used. I wanted to create a simple and powerful high-voltage generator powered by 220 volts. Such a generator was needed for the experiments that I put on regularly. The power of the generator is quite high, at the output of the multiplier the discharges reach up to 5-7 cm,
To power the horizontal transformer, an LDS ballast was used, which was sold separately and cost $ 2.
Such a ballast is designed to power two fluorescent lamps, each 40 watts. For each channel, 4 wires come out of the board, two of which we will call "hot", since it is through them that high voltage flows to power the lamp. The remaining two wires are connected to each other by a capacitor, this is necessary to start the lamp. At the output of the ballast, a high voltage with a high frequency is formed, which must be applied to the line transformer. Voltage is applied in series through the capacitor, otherwise the ballast will burn out in a few seconds.
We select a capacitor with a voltage of 100-1500 volts, a capacity from 1000 to 6800pF.
It is not advised to turn on the generator for for a long time or you should install transistors on heat sinks, since after 5 seconds of operation there is already an increase in temperature.
Line transformer was used type TVS-110PTs15, voltage multiplier UN9 / 27-1 3.
List of radio elements
| Designation | Type of | Denomination | Quantity | Note | Score | My notepad | |
|---|---|---|---|---|---|---|---|
| Scheme of the prepared ballast. | |||||||
| VT1, VT2 | bipolar transistor | FJP13007 | 2 | To notepad | |||
| VDS1, VD1, VD2 | rectifier diode | 1N4007 | 6 | To notepad | |||
| C1, C2 | 10uF 400V | 2 | To notepad | ||||
| C3, C4 | electrolytic capacitor | 2.2uF 50V | 2 | To notepad | |||
| C5, C6 | Capacitor | 3300pF 1000V | 2 | To notepad | |||
| R1, R6 | Resistor | 10 ohm | 2 | To notepad | |||
| R2, R4 | Resistor | 510 kOhm | 2 | To notepad | |||
| R3, R5 | Resistor | 18 ohm | 2 | To notepad | |||
| Inductor | 4 | To notepad | |||||
| F1 | Fuse | 1 A | 1 | To notepad | |||
| Additional elements. | |||||||
| C1 | Capacitor | 1000-6800 pF | 1 | To notepad | |||
| Horizontal transformer | TVS-110PTs15 | 1 | To notepad | ||||
| Voltage multiplier | UN 9/27-13 | 1 | |||||
Despite the abundance of complex converters, I decided to come up with a simpler circuit - for beginner radio amateurs. I didn’t come up with anything special, but it turned out to simplify the assembly process to the limit. Based on ballast from energy saving lamp. Structural scheme homemade plasma lamp:
It is best to take a 40-watt CFL lamp - it works quite stably, it even turned on for an hour, it works without problems. As a step-up high-voltage transformer, I used a ready-made horizontal scanning transformer TVS 110PTs15. I connected it to pins number 10 and 12. Such horizontal transformers can be found in old Soviet TVs, although you can take a new one, only they are produced with a built-in multiplier.
There are two outputs from the transformer: one phase, the other zero, the phase comes from the coil, and zero is the very last leg on the transformer (it is number 14).
We connect the phase to an incandescent lamp, and the other wire coming out of the zero leg should be grounded. In general, in the next photo, everything is painted and drawn in detail.
If you still do not understand something - watch this training video in HD quality:
Also, if you connect a voltage multiplier to the TVS outputs, you will be able to observe the glow of a fluorescent lamp from the generated HV field.
