I would like to build a frequency divider for bench use and could use some advice. What I would like to do is to use some of the thumbwheel BCD switches that I have (single digit) to make a circuit that would divide by whatever number that the switch displays. So if I turned the switch to 3, it would divide the input signal by 3, 9 would divide the signal by 9, etc. How would I go about doing this? A circuit that would work up to around 20 Mhz would work fine for my use.

Chris

 

Hi Chris
Try this site

http://www.wenzel.com/pdffiles/161divdr.pdf

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Regards,
Sarma.

 

I designed this circuit (I did not know about the web site) some months ago and have been testing it using 74HC163 (similar to the 74161).

However, as you can see in the attachment, mine is slighty different as I connected Tc to CEP not CET in order to speed up the output from the second Tc and I used a NAND gate (inputs connected to the Tc outputs & the output connected to the PE)

Edit. It does work at 20 MHZ, I had an error in my test arrangements.

However, if you only want to divide by 15 or less, then it works well since you only need one IC and so the Tc and CEP delays are not relevant.

Attached Thumbnails

 

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Len

 

Here is the scope picture. It shows the 1 MHz setting.

Attached Thumbnails

 

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Len