Delay circuit using battery

A delayed light circuit using electricity. Normally, the thyristor VTH is turned off and the iLi lamp E does not light up. When you need to turn on the light, you can turn on the composite tube composed of
FSH, VT1 and VTZ . The 9V DC power supply will be triggered by the gate input of the thyristor VTH through R, VT2. The current turns on VTH and the lamp F lights up. At the same time, the 9V power supply also charges the capacitor (1) through SB, allowing C to quickly charge to the power supply voltage. After releasing SB, the stored charge in C can be discharged to VT1 through R. The composite tube can still be maintained conductive, so the electric woman It will not go out until the charge base stored in C is discharged, VT1 and VT2 will enter the cut-off state from the on-state, VTH will turn off, and the light E will go out. The circuit delay time is mainly related to the discharge time constants of R, C ,The larger the value of R.,C is, the longer the delay time will be, and vice versa, the shorter it will be.