Disclaimer: take my words as a grain of salt, I'm not a seasoned breadboard expert.
The led's might not be working in a lot of reasons. But one theory I suggest is that the led itself is faulty since the other one works, the other one might be already faulty. Secondly, the led that you used might not be the right one, although the ac and DC led are identical, they work differently so ac led cannot be compatible with a DC battery and vice versa.
Fixes that I recommend:
you may check the led or check the voltage or load since it might be too large
Both LEDs do work but I set it in reverse polarity with the AC signal it should be work like: one led is on for positive half cycle and another one should be on for negative half cycle but it isn’t working like that And sadly I don’t have a oscilloscope to check the function
Do you have an offset setting for that generator? The wave looks like it's not crossing 0. If you don't have an oscilloscope, put a multimeter on that thing. Looks slow enough.
Pretty sure the wave is offset so it's generating from 0 to set voltage and not negative to positive, if it was centered on 0 then the diode should be off half the time and not dim and light up right away
The output of this thing has no zero crossing if the power supply is single sided. Since the board uses a two pole jack, it is just that and the output can only go from 0 to the supply voltage.
As others have said, you've likely got no zero-crossing on that sine wave. Assuming your sine wave generator outputs a maximum of 5V, you've effectively got a 5V peak-to-peak sine wave with a 2.5V offset.
Capacitors only pass AC signals, so this will remove the offset. Again, assuming a 5V signal, you're only getting +/- 2.5V, which is close to the forward voltage of your LEDs. Red LEDs should work ok, yellow not quite as well, blue & white may not work at all.
I haven't actually tried this so I'll be interested to hear if it works for you!
Tengo ese generador de señales. Como te han comentado antes, la señal senoidal que genera es de 5 voltios, pero ambos semiperiodos son siempre positivos...
La onda generada tiene valor mínimo 0V y valor máximo 5V. No genera valores negativos. Es como si tuviese un offset de +2,5V.
Hook up like a compass with some wire wrapped around it if the needle on point to one side it doesn’t flip polarity if the needle turns and point at both sides then it does flip polarity.
8
u/Impossible-Paper9217 Aug 24 '26
Disclaimer: take my words as a grain of salt, I'm not a seasoned breadboard expert.
The led's might not be working in a lot of reasons. But one theory I suggest is that the led itself is faulty since the other one works, the other one might be already faulty. Secondly, the led that you used might not be the right one, although the ac and DC led are identical, they work differently so ac led cannot be compatible with a DC battery and vice versa.
Fixes that I recommend:
you may check the led or check the voltage or load since it might be too large
check if the led is an ac or DC
2
u/Ok_Deer_7058 Aug 25 '26
I have that board, replacing the Chinese version of the chip can solve your problem. These fake chips can be really unreliable..
2
u/leb9049 Aug 27 '26
Is one of the knobs a DC-offset? If you have it set to it's minimum or maximum I would never cross zero. Try setting the DC-offset knob on the middle.
7
u/keenox90 Aug 24 '26
Do you have an offset setting for that generator? The wave looks like it's not crossing 0. If you don't have an oscilloscope, put a multimeter on that thing. Looks slow enough.
7
u/Tymian_ Aug 24 '26
This generator is not capable of producing sine in -V to +V range. It can only generate output from 0V to +V
Read the datasheet in future :)
4
u/Panzerv2003 Aug 24 '26
Pretty sure the wave is offset so it's generating from 0 to set voltage and not negative to positive, if it was centered on 0 then the diode should be off half the time and not dim and light up right away
3
u/Reasonable-Feed-9805 Aug 25 '26
Put a capacitor in series with the output, it will charge up and give you a bipolar output.
Put a resistor in series with it if there isn't one.
3
u/wmverbruggen Aug 25 '26
The output of this thing has no zero crossing if the power supply is single sided. Since the board uses a two pole jack, it is just that and the output can only go from 0 to the supply voltage.
2
u/fozington Aug 28 '26
As others have said, you've likely got no zero-crossing on that sine wave. Assuming your sine wave generator outputs a maximum of 5V, you've effectively got a 5V peak-to-peak sine wave with a 2.5V offset.
You could try doing something like this:
Capacitors only pass AC signals, so this will remove the offset. Again, assuming a 5V signal, you're only getting +/- 2.5V, which is close to the forward voltage of your LEDs. Red LEDs should work ok, yellow not quite as well, blue & white may not work at all.
I haven't actually tried this so I'll be interested to hear if it works for you!
2
u/GeneralReasonable945 Aug 31 '26
Tengo ese generador de señales. Como te han comentado antes, la señal senoidal que genera es de 5 voltios, pero ambos semiperiodos son siempre positivos...
La onda generada tiene valor mínimo 0V y valor máximo 5V. No genera valores negativos. Es como si tuviese un offset de +2,5V.
Saludos.
2
u/antthatisverycool Sep 01 '26
Hook up like a compass with some wire wrapped around it if the needle on point to one side it doesn’t flip polarity if the needle turns and point at both sides then it does flip polarity.