In a message dated 23/07/2002 19:01:28 GMT Daylight Time,
tufgaraj@MUSS.CIS.MCMASTER.CA writes:


> I know this is a bit of a stupid question but oh well.  :)
>
> I've got a 1.2V solenoid running off a 5V supply.  Right now I just drop
> the voltage with a resistor but this is wasteful as most of the power
> does not go to the solenoid, but is lost as heat in the resistor.
>
> I was looking around the net and saw that a better way to do a voltage
> drop is a zener, but isn't the same power wasted through the zener as
> the resistor?  Or is less wasted?
>
> I was thinking of using a voltage regulator but this seems like
> overkill.
>
> So what's a more efficient way to power the solenoid from the 5V supply?
>
> Thanks,
> Aaron
>
>
Depending on current required-
If you are just experimenting and the application is not critical, you could
use several diodes in series (0.6/0.7v voltage drop per diode)  or  even a
suitable wattage Zener diode - crude but inexpensive!

PWM would be more efficient, I can offer advice on dedicated PWM chips, but I
am sure the Piclisters can solve your problem with a pic!!!!

Regards

Kevin

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