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Re: LED Charge Indicator
Original poster: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>
Hi,
As I have always advocated... To the point of always offering
discharge resistors happily sent free to anyone that asks... It is
best just to add a bunch of resistors and just not worry about it ;-))
http://hot-streamer.com/TeslaCoils/MMCInfo/emmc04.jpg
Note that many caps, like Peter's, will recharge if left open after
being charge for a long time...
http://www.wima.com/absorption.htm
Discharge resistors fix all that ;-))
Cheers,
Terry
At 06:13 PM 10/9/2005, you wrote:
Neons are easiest and their rated current is less than 1mA (typ
600uA). I am using a system on my 10kV 8kJ cap with a resistor chain
of 20Meg (20 x 1meg x 1/2W) with a neon in series (ie switches on at
a low voltage of 70V). This is in series with a relaxation
oscillator with a ?.001uf cap 630V which is in parallel with 4
series neons. Experiment with the cap and the desired flash rate.
So visually you get a neon that is always on with any significant
charge, plus a flashing neon set that flashes faster with increasing charge.
I believe these are vital for high energy caps but not so much for
Tesla stuff, depending on your setup as the cap is normally
discharged through the power transformer when power is off unless
you have a DC setup.
I am sure you could do the same thing with a LED as the high output
LEDs (>5000mcd) will be very visible at 1mA average current. You
could use a flashing LED with appropriate parallel resistor or zener
to prevent over volting it. Also it will be polarised so need to
account for this as voltage reversals may occur depending on your application.
The other advantage of a light indicator is that it discharges the
cap to prevent dangerous voltages from hanging around and also
reaccumulating. My defib caps recharge by a few hundred volts if
you leave them open.
Peter
http://tesladownunder.com/
Original poster: "Dan" <DUllfig@xxxxxxxxxxxxx>
some industrial equipment that have built in capacitors, have a
red LED on the front panel to indicate if the capacitor is
holding a charge. Can this be done with the capacitors in a TC,
or are the voltages just too high?