Re: Ping Tester/ Complementary emitter-follower

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

Original poster: "Jolyon Vater Cox by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>

Antonio,
Are these steps you refer to like crossover distortion on a linear amplifier
or the dead-time (ie. the pause between positive and negative excursions
when the voltage is zero) on a Pulse Width Modulated half- or full-bridge
converter-might it not find application in such a role?
Do you have any oscilloscope pictures available of the waveforms?

How large do the step voltages need to be with regard to the +/-1.2
base-emitter voltage drop -would a 9volt battery be OK or does the voltage
need to be higher than this?

If single-ended emitter follower is used is it OK to substitute BC337/BFY50
for the BC307 you suggested for the output stage?

If complementary emitter-follower were to be employed after Pin 3, what
would be the best transistor types to use?

I am a bit concerned about having an "unlimited" current output on Pin 3 or
subsequent BC337 emitter follower stage because of the risk to the the
tester in the event that it is is accidentally connected to to
short-circuit. To prevent this, would it be possible to replace the real
tank capacitor with a low-voltage capacitor of the same
capacitance -permanently wired in series with the output stage of the
tester- during low voltage tests? Or do you just have to be careful not to
short-circuit the test prods.

Finally, would it be be to use a milliameter -connected between the battery
and the output stage- to give an indication of the rise in current
associated with the commencement of resonance?
Jolyon.

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, November 16, 2002 8:07 PM
Subject: Re: Ping Tester/ Complementary emitter-follower


 > Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>
 >
 > Tesla list wrote:
 >  >
 >  > Original poster: "Jolyon Vater Cox by way of Terry Fritz
 > <twftesla-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>
 >  >
 >  > Other than because of the 0.6 volt base-emitter voltage drop what are
the
 >  > reasons if any why a complementary emitter-follower outout stage cannot
be
 >  > used in a "ping tester" for Tesla coils?
 >
 > When the current changes direction, +/- 1.2 V steps appear at the output
 > of the buffer, distorting all the waveforms. Works reasonably if the
 > step voltages are much larger than this. Or you can add bias to the
 > transistors and/or make a more complex buffer with negative feedback
 > to keep the output voltage constant.
 >
 > Antonio Carlos M. de Queiroz
 >
 >
 >