I have a water tank with a built in simple 'float switch'. It acts like any other switch. Last year I tried connecting it to a buzzer so that I would know when the tank would be empty. This burnt out the switch almost instantly, so I came up with something much too complicated for my likings:
Some things to note:
- My battery system is 24v
- The timer relay is 12v (hence the transformer), when powered it connects the output pins for 5 seconds (the length of the alarm).
- I only added the entire 'switching part' to reduce the current, because when I would put the switch between the supply and transformer directly it would 'burn out' after 1 use.
From the start on I have found that the buzzer is not loud enough. So I am planning to 'upgrade' to a 12v buzzer with 85db. And I thought this would then be a good time to simplify things. See below:
- How do I avoid burning out the switch? I thought of adding a resistor, but at 12v and lets say 100ma (the pull in for the relay is 50ma and the nominal use of the buzzer 25ma), the resistor would get too hot, wouldn't it? The switch is rated 500ma max. fyi.
- Should I stick to the in my opinion over complicated old idea? I would like to make it a lot simpler and not have to use the extra 1.5v battery.