1
\$\begingroup\$

This circuit used to work before I soldered it. When I initially soldered it, I used a 6V battery and it was oscillating, but the speaker was very quiet. I went with a 9V battery and I re-soldered some other parts because the speaker would still not produce any sound. As well, the LED would have a voltage of around 8V on its turn while the speaker would only have around 0.03V on its turn (this stayed the same even after I switched their places and even replaced them). Right now, the speaker makes no sound and the LED (which previously flashed up with each oscillation) no longer flashed either. I checked with a voltmeter and voltage was still there across the circuit and across the loads. I can assure you that no soldered part is touching another (I know this cuz I've spent a day looking at them). I don't know what to do make the circuit function and for the speaker to make sound, please help.

enter image description here

\$\endgroup\$
11
  • 1
    \$\begingroup\$ I used a 6V battery and it was oscillating, but the speaker was very quiet. So the circuit was working, so that what you did after that broke it. You need to include a schematic before we can give a proper answer, use the schematic drawing tool that's available when you edit your question. Note that you might be expecting too much from this simple circuit. Include details of your speaker as it might have a low impedance and then it will be harder to get some volume out of it. \$\endgroup\$
    – Bimpelrekkie
    May 21, 2021 at 7:10
  • \$\begingroup\$ Photos of your "soldering skills" don't help so remove those. You have to determine (measure!) yourself if the connections are OK. \$\endgroup\$
    – Bimpelrekkie
    May 21, 2021 at 7:13
  • 1
    \$\begingroup\$ If you're new to soldering and have no experience how much is too much and had to redo a joint a few times, you might have cooked something. Here's a tip: ignore the rule that says to use a tip that is 2/3 as wide as the pad. Instead, use a pad twice as large as the pad if you can fit in. \$\endgroup\$
    – DKNguyen
    May 21, 2021 at 7:15
  • 1
    \$\begingroup\$ The only thing that I'd worry about permanently frying on that board is the LED. The soldering job is very poor and the most likely culprit. \$\endgroup\$
    – Lundin
    May 21, 2021 at 7:38
  • 1
    \$\begingroup\$ Are you trying to build a astable multi-vibrator like this: electronics-tutorials.ws/waveforms/astable.html. I would suggest to first test it using a bread board. I usually start with a bread board, then a proto board, and if everything goes well, and if I need more than a couple of it, then I will us PCB. \$\endgroup\$
    – tlfong01
    May 21, 2021 at 7:40

1 Answer 1

Reset to default
1
\$\begingroup\$

For loud sound you cannot drive the speaker through such a high impedance like 2k2. Also, your oscillator works at too low frequency (10Hz if pots are down) so it acts like a DC signal.

The circuit I attached below oscilates at about 1kHz and drives the speaker with higher power so the sound should be louder. Try to change C3 a little if necessary.

enter image description here

enter image description here

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.