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

flyback with a pulsed DC signal
Implantable-ingestible-electronic-thermometer
Inductance Meter Circuit
relay flasher circuit
Downlink Project Description
3-channel Audio Amplifier circuit
Light Detector
Combustible gas alarm circuit diagram 7812 7805 555
880MHz low-noise amplifier application circuit composed of RF2347



Top