I'm working on a project to make a (split) single-supply pulse generator. My main goal is to come up with something that can be easily tuned to a wide range of frequencies, produces a fairly stable and accurate square wave output, suitable for applications requiring low current consumption, and a configuration that's generic enough to be adapted to work with a variety of op amps. This is what I've got so far:
For the most part, the circuit seems to function properly. Here's a shot of the oscillator in action on the breadboard (I'm using the LM324 quad):
I have noticed however that when Rx and Ry are large values and Rf falls below a certain threshold, the output gradually attenuates to zero. For example, in the case where Rx = Ry = 1M ohms then the output dies out when Rf reaches around 12K ohms.
I also have a few questions for the experts:
For the most part, the circuit seems to function properly. Here's a shot of the oscillator in action on the breadboard (I'm using the LM324 quad):
I have noticed however that when Rx and Ry are large values and Rf falls below a certain threshold, the output gradually attenuates to zero. For example, in the case where Rx = Ry = 1M ohms then the output dies out when Rf reaches around 12K ohms.
I also have a few questions for the experts:
- Are there any inherent flaws in the design?
- Can the circuit be improved upon without compromising too much simplicity/flexibility?
- Are there any existing (well-tested) implementations out there that provide pretty much the same functionality?
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