Re: I need a switch can you help? IMPORTANT!

Kenneth Carrigan ( (no email) )
Thu, 29 Jan 1998 07:54:12 -0500

Opps.. one more thing - It contains a reverse diode or clamp that
is integral and you get it for free. So if you want to pulse a load
and then 'disconnect - open circuit it', the diode will clamp any
reverse current to ground. For example: Charge up an inductor
with the MOSFET, the when the 555 goes low, the MOSFET
goes to the high impedance state - except it contains a reverse
diode - so the energy stored in the inductor will be shunted to
ground. If this did not happen - you would blow any semiconductor
with the reverse voltage spike created by the energy in the inductor.
If this is what you are trying to do... no semiconductor that I know of
could withstand the reverse voltage spike (most overunity type
work requires this).

Sorry for the rambling...

v/r Ken Carrigan

>I need a *switching device sometimes called a "chopper" that has low
>resistance that can take more that 1 amp (I really need about 10 amps)
>and an adjustable frequency, I would like a range of at least 50>100hz
>but I am flexible and I really need an adjustable pulse width or one
>that is open about half the time.
>
>This is a very important part of a promising experiment I am trying, If
>you know of a place that makes such a switching device or of a model
>number ot anything please respond, I need a current that seems far to
>high for a 555 circuit or anything that I know like it and so I am
>expecting a rotating switch is what I will find.
>
>If you have any ideas of how I could make one, know were I should look
>or what I should by please respond.
>
>* A component of a circuit that will make and break the circuit so that
>a pulsed DC will result from a constant voltage source.
>
>
>Thank you in advance, John Berry
>
>