Double button light switch circuit (7)

It is a double-button touch type with good performance that adopts the "two-wire" connection method. The
left part is the ordinary lighting circuit, the bottom part is the light control switch, and M1 is the open touch diaphragm. M2 is the light touch H.
    A neodymium tube V D1 ~ VD-1 and a thyristor
VT3 form the main circuit of the switch. The
control loop is composed of transistors VT1 and
VT2. Normally, the thyristor
V113 is in the off state and the voltage does not
light up. 220V alternating current is rectified by V[)l -
VD-1, R. and R. When the human hand touches the -r Ml electrode piece, the human body induces a current and injects it into
the base of VT2 to conduct VT/. [The stored charge is passed through VT2 to (1. Discharge to (1.) The self-voltage is obtained at both ends, and is added to the f J pole of the thyristor VT3 through R*, causing VT3 to conduct, and the lamp is lit. By When the value of R is small, when V r{ is turned on, its gate leakage current can charge to C through R. Therefore, when people leave the electrical device fn, the voltage at C. A terminal remains unchanged, and the lamp always remains When the light is on, the electronic switch is in the "on" state. When you need the lamp, just touch the M2 electrode piece with your hand. The human body induced current is injected into the base of VTi through RV , causing VT1 to quickly conduct. At this time, C is stored The charge is discharged through VT1, causing the voltage at both ends to drop rapidly, and VT3 loses the trigger current. When the alternating current crosses zero, it is cut off, the lamp goes out, and the electronic switch is in a "fire" state. The function of C is to resist Interference can prevent the power supply voltage fluctuation from causing malfunction of the well.     VT1 and VT2 can use 9011, 9013 and other silicon NP] transistors, which require 7ceo ≥ 25V and port ≥ 100. VT3 uses ICR100_8, 2N656j type small plastic-encapsulated unidirectional thyristor. There are no special requirements for other components . When wiring, the phase and neutral wires of the 220V AC mains power must be connected as shown in Figure F, otherwise the circuit will not work properly . This connection method of phase wires is in compliance with the electrician’s wiring specifications. . The load capacity of this TR cylinder is mainly determined by the current capacity of VT3 and VDI - VD4 . The load power shown in the figure is below 100W. The load is suitable for incandescent bulbs, which is suitable for small inductive loads.