How to Make a Square Wave Oscillator from an OpAmp

Here's a simple way to build an astable oscillator from just a single OpAmp.In my case it was the LM358.
The frequency range is quite limited but it works quite wella s a substitute for the 555 Timer.
All resistors are 10k and Vcc can be between 5V and 15V or more depending on the IC.
Thanks for watching, I hope you enjoyed the video!
0:00 Intro
0:32 Circuit Explanation
2:00 Frequencies
2:35 Conclusions

[@PrinceWesterburg]

Brilliant - I build valve gear and so often none mentions parasitics but its both important and useful!

[@TimPerfetto]

I tried many other video's instructions but yours was the first that worked. I'm sure it's my fault but still, thank you

[@jugnu361]

very useful -------------------- Thanks

[@hobbytechnical1097]

Nice video dear and so helpful for me and my students thanks

[@rickyagostini4009]

I was waiting for the new video 💪🏼

[@5VLogic]

HAHA, so was I !

[@tnamen1307]

@@5VLogic when the output is 0v, the capacitor starts discharge. Now, I'm confused where the capacitor finds its ground to get discharge itself!!!! Is it discharged through the LEDs resistor??
Please little bit elaborate on this discharge process. Thanks.

[@5VLogic]

Great question, an important detail to remember is that the OpAmp's output can both source current and sink it, meaning if the capacitor is charged and the output is low, current will flow from the cap, through the resistor into the OpAmp's output since the latter is virtually shorted to ground.

[@davidjohnston5329]

Subbing just because of this vid.

[@michaeljoshuamanallo1742]

thanks I used lm348 but I use only one op amp inside the ic

[@techtheguy5180]

You have 555 subscribers

[@wingsofmind]

How to calculate the frequency? I'd like to know the formula

[@5VLogic]

Great question! Because the two voltages the cap needs to reach are 0.33 Vcc and 0.67 Vcc (assuming all resistors are the same) the formula is similar to the one for the NE555: T = 2*0.693*R*C => frequency = 0.72 / (RC)

[@wingsofmind]

555 has two comparators and one flip flop and one inverter accordingly, but it has only one comparator.
Anyway thank you so much sir. I work out again to get the desired frequency.....

[@wingsofmind]

Show me some calculation for that

[@allaoui38]

It’s not an explanation, it’s just a demonstration you know

[@hybridjohn1]

kaboom. wow, great vid