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Multi-layered Sec + batt
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From: Dale Hall [SMTP:Dale.Hall-at-trw-dot-com]
Sent: Monday, March 23, 1998 5:11 PM
To: Tesla List
Subject: RE>Multi-layered Sec + batt
RE>Multi-layered Sec + batt desktop TC
rejected(??): SMTP:aerpel-at-op-dot-net: 550 <SMTP:aerpel-at-op-dot-net>... User unknown
Hi Alfred,
I have been using battery power TC's regularily. I use conventional Pri & Sec's, a vacuum switch as a gap (quiet, - the only sound is the HV discharge: nice for the desk, and fast quenching and small ~2x1" "T" shaped - SPDT transmit - receive switch I believe was the original application), and a flyback for HVDC. One of the advantages of DC is that I can select larger value resonant Caps. For example with a .1 uF 5kVdc ruby mica (~2x1x1/8"), Pri=11"x1/8 copper tubing (tap 3-4T), Sec = 8.5"x20 #22, I get 8-10" discharges at 1-2 per sec using 9v batt at 40ma powering a 1" cube flyback extracted from an old camcorder's 1" monitor. (custom electronics could reduce the steady state current to a few mA). Going to much higher DC voltages, say 20-30kV much longer discharges are possible. The discharge rate is controlled by the current sourcing capability of the flyback - the more current that is available the faster the Cap charges to (RC) the more sparks per sec - at the cost of mo!
re input (battery) power required. This mode allows me to analyze on a storage scope each spark relative to the gap firing that caused it. For example the many on the list have been looking for a way to straighten out a jagged discharge to measure it. Using this controlled approach I've been able to do that electronically. i.e. longer path sparks show up as longer periods. On the above coil last evening using a 7" pointed Sec control, gap time to spark varied 9 to 12 us for the same pri energy (1.25J) and appears to represent varied path lengths of individual firings.
(boy, this IS fun!) Dale
From: Alfred C. Erpel [SMTP:aerpel-at-op-dot-net]
Sent: Sunday, March 22, 1998 7:03 PM
To: Tesla List
Subject: RE: Multi-layered Secondary
.... snip
It is approximately 1.5 OD x 5.7 high. Anticipated inductance is
approximately .1 Henry. 3.5 ohms resistance. Awesome Q. Something unknown
(to me) is how much distributive capacitance this type of coil will display.
At 50 picofarads, total capacitance (with top load), its frequency will be
71 kHz. This works out to a theoretical Q of greater than 12,000! (2 x pi
x freq x inductance / resistance )
I am planning for this coil to be run on my desktop, and hopefully battery
powered. And I still have not nailed the exact configuration of the power
supply feeding the primary. Right now I am trying to adapt the charging
circuit from a disposable flash camera as a power supply for this coil; I
have wound a small transformer and built a small spark gap to kick the 300
volts DC up to 9000 volts but I will probably need help on this (just tried
it this weekend with unclear results). I will post more on my small coil
as it develops.
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Date: 3/22/98 10:56 PM
To: Dale Hall
From: Tesla List