Re: OLTC - Re: Primary resonators with very low L/C ratio

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

Original poster: "Ed Phillips by way of Terry Fritz <teslalist-at-qwest-dot-net>" <evp-at-pacbell-dot-net>

Tesla list wrote:
 >
 > Original poster: "Jolyon Vater Cox by way of Terry Fritz 
<teslalist-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>
 >
 > The TC advertised by  Edmund Scientific
 > http://www.scientificsonline-dot-com/ec/Products/Display.cfm?CategoryID=197425
 > is also a "kicker-coil" i.e. it is an an OLTC using a mechanical breaker.
 >
 > It is interesting to hear the suggestion of replacing the breaker with an
 > electronic switch. With regard to this, how about using a blocking
 > oscillator, with  a feedback winding on the iron cored choke to maintain
 > oscillation, the TC primary and capacitor being connected in series across
 > terminals of the switching transistor, MOSFET or IGBT.
 > The blocking oscillator is electronic analogue of the induction coil, after
 > all!
 >
 > Jolyon.

	During WW2 blocking oscillators were used as radar transmitter
modulators, and some of the VHF radars operated in a blocking-oscillator
mode, with up to 15 kV DC on the plates of the triodes and grid leak and
bypass capacitor chosen so as to cause them to "block".  I'm sure the
same technique could be used with a TC (very high plate voltage, very
high emission oscillator tube) but have not had the ambition to try it.
It seems to me the subject was discussed here a year or so ago but I
didn't save the notes.

Ed