# LM324 squarewave oscillator adjust output frequency

## Main Question or Discussion Point

I have designed an opamp based on thfollowing square wave setup http://www.national.com/ds/LM/LM124.pdf [Broken] on page 11. I want to know what i would have to adjust to lower the frequency to the range of 10 hertz, it has a 5 volt input and the frequency range is at 10 Ghz I believe. any help would be appreciated.

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## Answers and Replies

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berkeman
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I have designed an opamp based on thfollowing square wave setup http://www.national.com/ds/LM/LM124.pdf [Broken] on page 11. I want to know what i would have to adjust to lower the frequency to the range of 10 hertz, it has a 5 volt input and the frequency range is at 10 Ghz I believe. any help would be appreciated.
If you mean the example square wave oscillator on page 11 of that datasheet, it most certainly does not operate in the GHz range of frequencies. The frequency will be around the RC time constant of the feedback shown. You may be able to get down to 10Hz with large enough values of R and C, or you could use a counter to divide down to 10Hz from a higher oscillator frequency. You could use a CD4020, CD4040, or CD4060, for example.

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The R1 feedback resistor in the schematic on page 11 probably should not exceed about 200K, because the input bias current is <= 200nA.

can oscillation be created without the the lm ic s if yes why and how bob s

can oscillation be created without the the lm ic s if yes why and how
Build a relaxation oscillator using a Ne2 neon bulb. See

http://www.cliftonlaboratories.com/relaxation_oscillator.htm [Broken]

Bob S

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vk6kro