Door Bell


Joined Mar 14, 2008
How about something like this, assuming the buzzer takes more current than the relay.
You adjust the value of R1 until both the buzzer and relay operate reliably.


Thread Starter

Big Dingus

Joined Oct 22, 2018
Bob. Finally.
13m on the SSR and 96m on the buzzer.
Because of space crutschow’s idea would be ideal, but obviously any that works is good for me.


Joined Jan 23, 2018
I said: "The right way to make the buzzer buzz is to add a third wire - a return wire. Connect the buzzer to the switched side of the switch, not the supply side. When you push the button the buzzer will buzz. But at 18 volts - you're going to have to add in some resistance so you don't burn up the buzzer. To figure the correct size resistor you need to know the resistance of the coil of the buzzer. Then you need to make a voltage divider (resistor in series with the buzzer) so that the resistor drops 12 volts."

"And likely it's going to be a pretty big resistor, wattage wise."

This shouldn't affect the SSR whatsoever.

Here's what I had in mind when I said adding the third line:

View attachment 200508
The TS has stated that adding wire would be difficult. THAT is why the buzzer would be IN SERIES with the SSR, and why I suggested a resistor across the SSR, so that there would be more current through the buzzer.


Joined Jun 5, 2013
A 125 Ohm resistor across the SSR should do it. This will drop 12V at 96 mA leaving 6V for the buzzer.

Only question the is whether the SSR will trigger at 12V, which I think is likely.


Thread Starter

Big Dingus

Joined Oct 22, 2018
Folks I managed to get time to attack this today.
I opted to try across the SSR as it was indoors and not standing out in the wind, cold and rain.
100ohm did the trick.
I wish I had your knowledge.
Anyway many thanks for helping me and others. Most appreciated.
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