Figuring out Duty Cycle component values

Thread Starter

Scott McKie

Joined May 26, 2013
4
I have to figure out the RC (resistor and capacitor) component values for the dual variable duty cycle output from a HCC4098B Dual Monostable Multivibrator with a dual 16 kHz input frequency from a 4027 flip-flop chip.
It looks like a 0.1uF capacitor would work, but I can't find any info on whether or not an electrolytic capacitor is required or not. Also; there is no info on what the best variable, multi-turn resistor value, would be. I can get the thing figured out the old fashion way -- pick and solder, then unsolder and change, but help on this would really help.
The duty cycle also needs to be as close to "0 to 99%" on both outputs, again at 16 kHz outputs.
Thanks in advance for any help on my questions you can send my way.
 

MrChips

Joined Oct 2, 2009
30,708
You don't want to use an electrolytic capacitor as the timing element in a monostable multivibrator. Polarization in the dielectric will result in inconsistent timing.

Look up the datasheet of the monostable and you will find timing graphs for different resistor and capacitor values.

For better results, use a 4538 dual monostable multivibrator.
 
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