audioguru said:
Why use a relay with such a high current coil?
Why use a relay? Why not use a low current transistor or triac?
You didn't attach a schematic of your circuit so we can't see what is shorting the transformer. The transformer is ruined from overheating, is dangerous now and should be replaced.
Thanks for the reply audioguru.
>>Why use a relay with such a high current coil?<<
New to electronics I guess. I just bought it from the shop only looking at the 5v coil as my circuit runs on 5v (but I know now the 4060 chip I bought does not have to have 5v – I thought it did. Used a 5v regulator could not be bothered to change it).
Actually (please don’t laugh) the 5v relay causes a 12v relay to energise (using yet another 9v batt)!
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I originally had the 12v relay only. I used a transistor to try to get it to energise. It refused. As the circuit was 5v I guess. I even tried to connect the emitter to the 9v +ve of the battery and not the 5v regulated line. It still refused to energise. (I think I was working with a flat battery that day anyway).
Why the 12v relay you say? The 12v relay contacts are connected to a washing machine. The relay said 10A. But then I read something about inductive loads. This relay only does 3A inductive loads. I believe washing machines are inductive loads? How many amps will a washing machine draw?
Why do I want my washing machine on a 2hr timer you say? I was making a crude pay washing machine for a house that I let. You drop in £1 – the £1 hits a micro switch with lever – this then starts the 2hr timer, which gives about 1 wash cycle which is 2 hrs. (It all works like a dream by the way. I have only tested it with a fan not washing machine as Im not sure if my relay is adequate. It is only triggered by £1 as 5p 20p 1p are too light to trip the switch)
>>Why use a relay? Why not use a low current transistor or triac?<<
I have not read that chapter yet ;-) Are there Triacs that can handle washing machine currents?
As for the circuit diagram, I modelled it on this
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Timer 2 is the circuit I used.
My rectified 9v (W08 bridge rectifier) supplies my 7805 which supplies my circuit and 5v relay. My 5v relay contacts then supply my 12v relay coil with power from the unregulated but rectified 9v supply.
So I am shorting my transformer with the 12v relay which I thought I could do (is that what you mean by what is shorting your transformer).
(I wanted to test the ac current but found out my VM only does DC current. And I have not tested the dc current with the transformer in place. I have only done that with the 9v batt.)