Delay high voltage switch circuit analysis

This time delay switch can be used for delaying the speaker of the amplifier and avoiding the sound of the power-on impact. It can also be used for the picture tube. The tube circuit delays the high-voltage power supply to warm the filament and prolong the life.
The circuit is shown in Figure 23.16. It consists of 555 and relay J1. When the switch K is just turned on, the power supply is charged to C through R. The second and sixth pins of 555 are high level, the third pin is low level, and J1 is not released. When the delay is 1.1RC(s), the 555 output goes high. J1 is sucked, and the normally open node is connected to the high voltage Vμ for power transmission.
The delay time can be set arbitrarily according to the R and C values. J1 can use HG4099 type 6V electromagnetic relay.