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Topic: Having problems with relays!!! (Read 482 times) previous topic - next topic


guys i need help.. my relay doesnt change contacts...

i followed the tutorials in making a circuit with relay

i use a 5volts relay
bc548 npn transistor
1k resistor
and a diode parallel with the coil of relay...

the problem is... when i try to read the voltage readings across the relay it is only 1 or 2volts...
i also try putting a different transistor like ksp2222a... still i got the same results...

i connect the output of arduino series with a 1k resistor to base of transistor and emitter to ground and collector to coil of relay parallel with a diode then connected to 5volts supply from arduino...

help me pls


when i try to put higher dc voltage like 10volts instead of 5volts of arduino the transistor is getting very hot
and still got the same results...


Jan 26, 2012, 05:20 pm Last Edit: Jan 26, 2012, 05:21 pm by be80be Reason: 1
You want to hook your relay up as shown

It sounds like you have the diode backward

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