Incandescent Yeonsu switching circuit

Is another kind of connection switch incandescent spider life extension, it has two functions: First, just by electroporation,
Incandescent Yeonsu switching circuit - schematic

can be semi-crossing buck starts, to be fully preheated filament is transferred to full voltage power supply; second, once the city electric grid voltage than standard 220V high value ... about 20V, the circuit can automatically power down to a half-wave, the "effective extension K white incandescent lamp life make H1. after closing switch S, a half weeks when the AC is - when the power supply through Vn1, R ,, VD2 to the capacitor (seek power, (I-what ends pressure gradually increased, but far below the steady pressure of the pipe vs rJ threshold voltage, vs Chi is off, because there was no trigger current thyristor VTH in the off-state, then the light bulb E AC current flows in the negative. half cycle, the current through VD3, R, to mention VTH touch land for negative pull current, the VTH opened, light bulbs I: there are half-pay Xu electricity to warm up. as long as C is less than the voltage across the regulator I vS straight, in an alternating cycle of stars, the current flowing through E of only half a cycle, which soft-start drawer lamp. over time the shift, r voltage across the rising, when the rose and exceeded vs voltage value, VD2 reverse bias is turned off, it vs conduction through the power through VD1, r. VTH to provide trigger current, so the positive half-cycle alternating current star, VTH also opened on, then F enters full voltage power state. this circuit soft start time mainly by the capacitor (capacitance value determination 1. If the grid voltage suddenly knife high and exceeds the circuit did not count value, the transistor VT1 base sampling voltage rise high , wri mountain original flip off state to a conducting state, then (storage charge will VT1 discharge, vs recovery complex off the circuit and return to the original, r wave down wins power state. Kuai test: disconnect VD2, after closing r S, E should normally stop light. then turned VD2, Po and the RP's spin radially movable end side, so that VT1 into oFF state. At this time powered E can be observed after the first dark light soft start too soft flat dynamic process time t if undesirable, adjustable C capacity is then connected to the input AC voltage regulator circuit of the terminal, the voltage adjusted to about 2-10V, with a small screwdriver to fine-tune RP, just make VT1 As of that observed light bulb F can suddenly go dark.

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