I have returned to an old project and just need a bit of advice about component selection. This was the original thread but I have done away with the 555 and am feeding the LM567 ouput to an ATTiny. I have the code written and working great. I have the circuits designed and built for my device and it works as expected, so now I am just trying to understand what each part does, and how to make it as good as possible.
I am much better at programming and digital electronics than the analog side, so any help is greatly appreciated.
Here's the LM358 part of the circuit...
I found this guide here, which helped explain it a little.
So first question is about the mic. I am using this one, which says that RL should be 300R to 5K. In my circuit I have been using 10K and it still works, why?
Next up is the caps, that guide says their values are calculated based on the frequency range of input signals. How do I calculate them? I am wanting to listen for tones between 1Khz and 3Khz.(You can't see my C2 in the picture but I am using a 10UF)
Lastly his circuit doesn't have a resistor between C1 and the negative input of the LM358, while most of the other circuits I found do. What does it do and does it's changing its value do to the circuit?
Thanks for taking the time to read, and any help is much appreciated.
Regards,
Les
I am much better at programming and digital electronics than the analog side, so any help is greatly appreciated.
Here's the LM358 part of the circuit...
I found this guide here, which helped explain it a little.
So first question is about the mic. I am using this one, which says that RL should be 300R to 5K. In my circuit I have been using 10K and it still works, why?
Next up is the caps, that guide says their values are calculated based on the frequency range of input signals. How do I calculate them? I am wanting to listen for tones between 1Khz and 3Khz.(You can't see my C2 in the picture but I am using a 10UF)
Lastly his circuit doesn't have a resistor between C1 and the negative input of the LM358, while most of the other circuits I found do. What does it do and does it's changing its value do to the circuit?
Thanks for taking the time to read, and any help is much appreciated.
Regards,
Les
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