need circuit suggestion

Thread Starter


Joined Nov 25, 2018
Looking for a complete ready made circuit that makes constant 50% duty square waves up to 1MHz - 2 MHz at the turn of a single potentiometer.


Joined Mar 14, 2008
Generally the term "Complete ready made circuit" is considered here to be the same as a "complete ready made product".
So what you want (I assume) is a complete, tested, circuit schematic with a parts list.

How wide a frequency range do you expect with one pot twist?


Joined Sep 24, 2015
Two distinct impressions I got:
1) "I want a complete ready made circuit".
2) "I want someone to engineer the circuit for me".

1) There are plenty of off the shelf parts that are generally considered to be complete ready made circuits; and 2) We help each other figure out our circuits and other problems. We DON'T expect someone to engineer a solution to a problem we present. The services of those engineers who do as you're asking also charge a hefty price for their knowledge, experience and expertise.

I will give you this: A flip-flop can give you a perfect 50% duty cycle. You'd have to research the data sheets for such flip-flops to find one that can operate within the range you seek. But then you'll also need to build a clock circuit to drive the flip-flop capable of those speeds.

Turning a pot to switch from 1 MHz to 2 MHz? Instantainiously? If so - you'd be better off with a switch. Better yet, since many flip-flops come in dual packages, you can use one to give you a 2 MHz 50% duty cycle running on a clock that is giving you 4 MHz output. Use the second flip-flop to divide by 2. In other words, with the flip of a switch you go from 1 MHz to 2 MHz and back again. No pots needed.

If I'm not understanding you correctly and you want to sweep through the range from 1 MHz - through all the frequencies between 1 and 2 MHz and up to 2 MHz - THAT is done with the clock.