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General Mach Discussion / Re: Spindle On Off Setup No 5VDC at relay.
« on: April 27, 2011, 01:20:39 PM »
You need a driver circuit of some kind to drive the relay. The 5 volt that you are measuring is the voltage from the computer LPT port and that only sources a couple of milliamps and is not enough to drive a relay on it's own.
You could use an opto isolator, the output side would need a separate 5 volt supply to power the relay.
You could use a TTL gate, again a 5 volt supply would be necessary.
You could use a different BoB which already has the relay and drive circuit.
There are many options.
Tweakie.
You could use an opto isolator, the output side would need a separate 5 volt supply to power the relay.
You could use a TTL gate, again a 5 volt supply would be necessary.
You could use a different BoB which already has the relay and drive circuit.
There are many options.
Tweakie.