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single pulse

theredstealth

Sep 15, 2011
3
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Sep 15, 2011
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I'm building a circuit and I need it to send out a quick pulse when powered up to set a 4029counter to a certain value every time. I can not come up with anything.
 

KMoffett

Jan 21, 2009
723
Joined
Jan 21, 2009
Messages
723
You need a "power-on reset". Capacitor and resistor in series across power supply. Capacitor to Vdd and resistor to Vee. Junction of resistor and capacitor to CD4029's Preset-Enable...pin 1. How fast is the clock input? Try a 10KΩ and a 0.1µF. Depending on the CD4029 counted circuit, you might want to add a 1KΩ resistor across the Vdd to Vee. This is to assure discharge of the added capacitor when power is removed.

Ken
 

theredstealth

Sep 15, 2011
3
Joined
Sep 15, 2011
Messages
3
Thank you for the info
Clock will be controlled by switches. Solenoids will be controlled by counter output as well 7-segment display.

So if I understand you correct, Vdd is power and Vee is common. which means;
Power------>Capacitor------->P/E & resistor----------->common
 

theredstealth

Sep 15, 2011
3
Joined
Sep 15, 2011
Messages
3
thanks for the help, we just had an example of this in class today, if I had asked this question I wouldnt have realized the purpose of the circuit and it would have been just another diagram. now I know how it actually works.
 
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