From: Terry Pinnell
Subject: Re: zero-power toggle circuit; was, how to master electronics
Date: Tue, 19 Nov 2002 15:06:07 +0000
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NNTP-Posting-Date: Tue, 19 Nov 2002 15:06:23 +0000 (UTC)
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>Terry Pinnell wrote:
>> But I'm still hoping to hear from circuit's sponsor, Win, or original
>> author, Wafer. Particularly interested to know whether Wafer built it
>> *only* with that specified low-power MOSFET, BS110?
>I think the
>version with the P-ch MOSFET worked down to about 6.5-ish volts. I
>believe I tried up to about twelve, but since the idea was for 9V, going
>up higher was not too important. I made the voltage divider off the
>output (with the 220K) such that the turn-on and turn-off
>characteristics were about equal. That is, it would take about the same
>time for the circuit to prepare to switch on as it did to switch off. To
>test this, I simply pressed the switch faster and faster until it
>favored one state over the other, then adjusted the resistor value to
>even it out, until it switched one way just as easily as the other, not
>favoring one state too noticeably. Very scientific, ah? I don't care if
>it doesn't check out in some computer model. I built it, and it worked.
>I know that if I stick with the one manufacturer of 2N7000's, there
>shouldn't be a problem. I did not test with high current P-ch MOSFET's.
>Again, 9V operation. I recently ran into a postit-note with a similar
>circuit I drew up for switching a power transformer. I think it's the
>same as the phone one (only bipolars), so maybe I'll try that and post
Thanks. That seems to confirm that the original circuit (as re-drawn
properly by Jonathan and Win), and on which I did the simulation, was
not tested on a range of MOSFETs, only on the low current BS110.
Hobbyist, West Sussex, UK