555 learning time too long reminding circuit

Published:2011/5/23 7:31:00 Author:TaoXi | Keyword: learning time, too long, reminding circuit | From:SeekIC

This learning time reminding circuit will remind you every one hour when you are learning or working to protect the eye and the body. This circuit is composed of the integral point lightspot coupler, the trigger control circuit and the controllable audio oscillator.etc. The circuit is as shown in figure 16-32. The integral point is led out by the digital clock tenths unit LED digital tube's b segment. Under the action of the integral point moment jumping signal, the IC1's phototransistor has the low resistance, VT1 conducts, VT2 is in the saturated conduction state. IC2 uses the time base circuit 555, and the monostable trigger is composed of the time base circuit 555 and the R2，C2.



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