Phase regulator of capacity

For adjustment of capacity many circuits are created, but radio fans continue experiments in search of the optimum. Existing circuits of PHASE adjustment of capacity, though involve with the simplicity, but possess one essential shortcoming - at change of mains voltage it is necessary to select anew control mode by a simistor for this capacity. Besides, you see, to regulate capacity a potentiometer inconveniently, especially if it is necessary to come back periodically to earlier set modes.

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the Offered circuit (fig. 1) is based by p on a principle of phase adjustment of capacity in loading in the discrete way. Let's consider circuit work when the SA1 switch is established in situation 10.

of the Fig. 1. The schematic diagram of a regulator of capacity

Mains voltage of 50 Hz (fig. 2á) via the restrictive R1 resistor arrives on diode Bridge VD1. . VD4, becomes straight, thus frequency of impulses doubles (fig. 2í) the Clock pulses limited to resistors R4, R5, arrive on an entrance (a conclusion 1) DD1.1. During the initial moment of time on an entrance of 1 chip of DD1.1 - logic "0" thereof on an exit of 3 DD1.1 there will be logic "1" (fig. 2ó) which will start the generator on the elements DD1.3, DD1.4. The generator is adjusted on frequency of 1000 Hz. At connection to a network, impulses with frequency of 100 Hz, having passed through the VD9 diode, charge the SZ condenser. During this moment there is a DD2 counter dumping. The C2 condenser, tension with which is at the same time charged, VD10 limited to a stabilitron, serves for a food of chips.

of the Fig. 2. Schedules of tension

Impulses from the generator fill with p the DD2 counter. After the 10th impulse on an exit of Q9 DD2 there is logic "1" (fig. 2ú) which via the R8 resistor opens the VT1 transistor switching an optodinistor of VU1. The last via the diode VD5 bridge... VD8 includes VS1 simistor. The capacity in loading thus will be minimum as the simistor opens at the end of a half-cycle of mains voltage (fig. 2ñ).

At the same time with VT1 opening, via the C1 condenser occurs RS trigger DD1.1, DD1.2 dumping, and via the R9 resistor - the DD2 counter. Duration of impulses of dumping and opening of a simistor depend on face values of R9, R11, SZ.

to

If the SA1 switch to establish in situation 1, opening of a simistor occurs at the first coming to a DD2 counter entrance an impulse from the generator (fig. 2Ñ) In this case capacity allocated in loading will be maximum.

the Provided circuit contains one switch and one counter therefore step-type behavior of switching of capacity is equal about 10 %. For smoother change of capacity (reduction of step-type behavior of adjustment) it is necessary to establish additional counters and switches. All entrances of dumping of counters unite, from an exit of the first switch the signal is got on a clock entrance (an entrance C) the second counter etc. Resistors R8, R9 are connected to the last switch. It is necessary to increase also frequency of filling of counters (2, 3, 4 kHz etc.).

Accuracy of installation of capacity depends, generally from drift of frequency of the generator. If big accuracy is necessary, I recommend to use the kvartsovanny generator of clock impulses shown on fig. 3. Certainly, the disorder of adjustment of capacity at the expense of instability of a network both on tension, and on frequency remains.

of the Fig. 3. The generator of clock impulses

the Device is assembled by p on the printed-circuit board in the sizes of 55x80 mm (fig. 4). All details, except the SA1 switch, are placed on a payment. SA1 is mounted on the forward panel of the device. The loop connecting the switch to a payment, should be no more than 25 see

of the Fig. 4. Printed-circuit board of a regulator

Detail

. Simistor in this device it is possible to apply any. Only the adjustable capacity depends on it. VD10 stabilitron - any with tension of stabilization 9... A series 561 can replace 15 V.Mikroskhemy on 176th. Then the stabilitron with tension of stabilization of 9 V.Kondensator S4 is necessary it is desirable to apply with the smallest temperature drift. The VT1 transistor is replaced with any of the series KT315, КТ3102. VD1 diodes... VD9 - with the maximum return tension 300 In and a current 100... 300 мА. SA1 - any on 10 provisions and one direction.

the Regulator was successfully tested by p and with optotiristor TO125-12,5. Light-emitting diodes of optotiristor incorporated consistently, and target tiristor - counter in parallel. Face value of the R6 resistor decreased to 220 Ohm.

Author: Village ABRAMOV, Orenburg, e-mail: [email protected]

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