555 audio equipment turn-on and turn-off

Published:2011/7/11 23:08:00 Author:TaoXi | Keyword: 555, audio equipment, turn-on, turn-off, | From:SeekIC

When you are tuning on or tuning off the audio equipment, the audio equipment circuit has the process from the temporary stabilization state to the stabilization state, so the speaker will send out the sound of pu , this circuit can eliminate this sound by using two pieces of 555. As the figure 14-23 shows, when the power supply turns on, the trigger which is composed of the IC1(555) and the relay J1 which is controlled by VT1 are connected to the main circuit power of the audio equipment, the delay time is about 2 seconds and then connect the speaker, so the sound of pu when you are tuning on the equipment is eliminated; when you are tuning off the equipment, because the pin-4 of the trigger IC2 is connected with the ground, so the IC2 resets, and it firstly cuts off the speaker through J2, the delay time is about 1 second, then it cuts off the main power of the audio equipment, so the sound of pu is eliminated.



Reprinted Url Of This Article:
http://www.seekic.com/circuit_diagram/Signal_Processing/555_audio_equipment_turn_on_and_turn_off.html

Print this Page | Comments | Reading(3)