555 radio automatic sentence spliting playback circuit

Published:2011/6/14 7:22:00 Author:TaoXi | Keyword: 555, radio, automatic, sentence spliting, playback circuit | From:SeekIC

When there is the playback signal, the signal is rectified by D1 to conduct the VT1, and C2 discharges. The 555 is in the set state, the LED turns on, the VT2 conducts, the motor M starts working to send out the sound. When sentence is over, the VT1 cuts off, the C2 is charged by R1, after about 1 second, when the voltage of C2 is higher than the threshold level 2/3VDD, the 555 resets to output the low electrical level, the M stops working. At the same time, the C3 discharges to the disrharge tube of 555 substrate through R3, when the voltage of C3 is lower than 1/3VDD, the 555 sets again, pin-3 has the high electrical level, M stops working. The discharging time tdischarge=1.1R3C3, the tdischarge of the figure parameters is about 10 seconds for the follow reading.



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