Re: Hvguy-dot-com Feedback SSTC and New Stuff!!!

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "K. C. Herrick by way of Terry Fritz <twftesla-at-qwest-dot-net>" <kchdlh-at-juno-dot-com>

Jolyon-

I believe I see what you are getting at...but it won't work.  You need a 
linear amplifier directly following the network in the return-circuit of 
the secondary.  The signal there is no more than noise initially, then 
increases to only ~+/- 0.7 V because of the diodes.  You want the diodes so 
as to limit the voltage excursion when the oscillations build up.  For that 
amplifier, I just use 3 CMOS gates "linearized" with ~100 K feedback 
resistors and capacitor-coupled.  The 3 must be in two ICs, not just one, 
to avoid deleterious substrate-coupling.  The output of the 3rd one will be 
pretty much a 5 V square wave all the time.  Circuit noise in that 
amplifier chain should be sufficient to get things started.

You could use, perhaps more efficiently, a single op-amp to drive the 
following logic-level gates.

The next CMOS gate in the line will provide a firm square wave, and then 
one more can be used, with a switch, to select the correct 
positive-feedback phase for the subsequent stages.

Ken Herrick

On Thu, 14 Nov 2002 08:01:34 -0700 "Tesla list" 
<<mailto:tesla-at-pupman-dot-com>tesla-at-pupman-dot-com> writes:
 > Original poster: "Jolyon Vater Cox by way of Terry Fritz
 > <<mailto:twftesla-at-qwest-dot-net>twftesla-at-qwest-dot-net>" 
<<mailto:jolyon-at-vatercox.freeserve.co.uk>jolyon-at-vatercox.freeserve.co.uk>
 >
 > Ken,
 > With regard to common base circuit reconfigured slightly to include
 > a 1k
 > resistor
 > would this work if Phases 1 & 2 instead of being used to drive the
 > fets
 > directly were used to drive an amplifier which would drive
 > the fets say, via a pulse transformer?
 >
 >                          +ve supply rail
 >  > >                    |
 >  > >                    R1
 >  > >                    |
 >  > >                    +-------Phase 1
 >  > >                 c |
 >  > >                    \
 >  > >            NPN |---------GND
 >  > >                e /
 >  > >    sec         |
 >  > >    |              |
 >  > >   +--1K----+
 >  > >   |               |
 >  > > c1           e \
 >  > >   |       PNP |----------GND
 >  > >   |            c /
 >  > >   |               |
 >  > >  +---------------------GND
 >  > >                   |
 >  > >                  +----------Phase 2
 >  > >                   |
 >  > >                  R2
 >  > >                   |
 >  > >                  -ve supply rail
 >
 >
 >
 >
 >
 > (The circuit I have shown is basically a non-inverting
 > voltage amplifier. The emitter-base junctions of the NPN
 > and PNP transistors act in the same way as the
 > back-to-back diodes in the setup you described -switching
 > on the respective transistors whenever voltage across
 > them goes above and below 0.6 volts, positive or negative
 > of ground)
 >
 > Jolyon.
 >
 >
 > ----- Original Message -----
 > From: "Tesla list" <<mailto:tesla-at-pupman-dot-com>tesla-at-pupman-dot-com>
 > To: <<mailto:tesla-at-pupman-dot-com>tesla-at-pupman-dot-com>
 > Sent: Thursday, November 14, 2002 1:58 AM
 > Subject: Re: Hvguy-dot-com Feedback SSTC and New Stuff!!!
 >
 >
 >
 >