Cmos-precision-programmable-laboratory-timer


Posted on Oct 18, 2012

The time base is first selected with Sl set for seconds or minutes, then units 0-99 are selected on the two thumbwheel switches S4 and S5. Finally, switch S2 is depressed to start the timer. Simultaneously, the quartz crystal-controlled divider circuits are reset, the ICM7250 is triggered and counting begins.


Cmos-precision-programmable-laboratory-timer
Click here to download the full size of the above Circuit.

The ICM7250 counts until the preprogrammed value is reached, then, the value is reset, pin 10 of the CD4082B is enabled, and the buzzer is turned on. Pressing S3 turns the buzzer off.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

12v 10 LED battery monitor
Light Controlled Relays
IR repeater with 555 timer
Simple color organ
AC100 sound mixer
4017 gate sequencer
AF counter circuits
Frequency Modulator and Tuning Circuit
make tv transmitter
Simple circuit diagram repellent
Fast charging circuit TEA1102



Top