Fig. 1.Fig. 2.Simply by touching the sensing element and actuates an electronic device that includes an alarm or actuator. The sensing element Ан1 — plated plate connected through a resistor R2 with a grid of thyratron MTX-90 (Fig. 1). The potential appearing ka the grid of the thyratron when you touch the plate, sets fire to it. The resulting circuit mtkh-90 pulses through the capacitor C2 is transferred to the SCR Q3 and the load (relay, lamp, siren, etc.). The circuit is powered directly from the mains alternating current. The capacitor C1 plays the role of damping resistor.

The second device (Fig. 2) it is convenient to use to enable the housing call. This scheme is powered by direct current. The half-wave rectifier is made to the diode D3, the capacitor C1 serves as a filter. Resistor R3 limits the current in the RL circuit, D1.
Instead of SCR КУ201А you can use any other, choosing it as follows. Consistently with timestorm to the network with voltage of 220 To include an incandescent bulb of 25 watts. If the lamp does not light, the SCR is suitable for the circuit relay “touch”.
Zener KS 630 can be replaced by COP 620А. Resistors — MLT, sun. Capacitors — MBM 300 V.

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