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Author Topic: DPDT 2 Coil Relay Problem  (Read 2013 times)
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Solder is electric glue
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Because with the load in the emitter you can only ever get the voltage on the base minus 0.7 volts on the coil no matter what voltage the collector is going to.

Where as if the load is in the collector you can get a voltage across the coil equal to the voltage to the other end of the coil minus the saturation voltage Vsat of the transistor.
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Aha! That makes perfect sense. Thanks.
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Is this circuit necessary if I am using 3V relay??
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I don't think you connected the grounds, Dave.
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Is this circuit necessary if I am using 3V relay??
What is the coil resistance?
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Is this circuit necessary if I am using 3V relay??
What is the coil resistance?

The resistance of the coil is 129 ohms
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