Re: TI-H: Electronics junk
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Re: TI-H: Electronics junk
Cmutr@aol.com wrote:
> I hope that description wasn't too cryptic for you- its much like a
> transistor, but it has 4 leads instead of three(common ground). Same purpose,
> different approach. (And its either off or on-secondary current doesn't
> fluctuate with primary current)
Actually, transistors should not be used to substitute for a relay.
Relays
are usually used to let low voltage circuits switch heavy loads -- loads
which could
damage any transistor, and, if improperly connected, the device
controlling
that transistor. For AC circuits you could consider a triac, but in
general
its electrically safest to use a relay. Transistors can indeed be used
as simple
amplifiers, but there are many other additional uses, for which relays
are wholly
unsuited. They both have their specific applications, in other words.
As a side note, you should have a clamping diode on the coil of a relay
to prevent
dangerous back-EMF. The diode will prevent any current produced by a
collapsing
magnetic field from making it into your circuit. You want to connect the
diode so
it conducts in the direction OPPOSITE how you normally power the coil.
Regards,
--
Bryan Rittmeyer
mailto:bryanr@flash.net
http://www.flash.net/~bryanr/
References: