Hi all,
I'm working on a project which requiring using 230v relays.
I've used this schematic
It works perfectly.
I've also two speakers connected to the same main power source, and I can hear some blop sounds through the speakers when the relays are switching.
How can I fix that ?
What are you switching with the relay?
Weedpharma
3x Light bulbs 25watts
When first turned on, the lights have very low resistance so there is a current surge for a very short time. This is probably causing the noise. Try using another power outlet a distance from this one causing the problem.
Weedpharma
weedpharma:
Try using another power outlet a distance from this one causing the problem.
Is there any schematic that will stop this "return current" or "current surge" ? like an 1n4004 diode used in electronic
To test the theory, move to another power point.
Once you know what the cause is, then look for a solution.
Weedpharma
I don't get any noise from another AC source.
But I need to use the same, what can I do ?
The pickup is before the amplifier that drives the speakers, this is where the audio signal
is small and vulnerable to pick-up. Is that physically close to the relays or their wiring?
If so move it.
No they don't.
I'm thinking there is something with power
when a relay is swiching a 25watt light, I can hear a little "pop" in my speaker
when the same relay in switching on and off a 75watt light, I can hear a louder "pop"
This suggests that the load is causing a dip in the supply due to current draw. I would not have expected 75W to cause much problem.
Weedpharma
Its not a dip in supply, its electromagnetic interference to the parts of the audio circuit
where the signals are small, you need distance, shielding, RFI suppression, careful
attention to ground layout to deal with such an issue.
You could try using a solid state relay instead of the mechanical relay. The mechanical relay opens and closes anywhere in the AC sine wave. A "zero crossing" solid state relay opens and closes exactly at the zero mark of a sine wave which is the noise-free location. There may be other issues as well, but it is easy to install a SSR and try it out.
Hi,
What is your amplifier, how long are the speaker leads, long leads act as an antenna and with EMF from the relay switching feedback to the low signal input of your amplifier.
What do you have connected to your amplifier?
Tom..... 