[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: LED Charge Indicator



Original poster: BunnyKiller <bunikllr@xxxxxxx>

I would say that the voltages are a bit too high, the required resistance to keep the LED lit at upper end voltages would be in the near 1 megaohm rating. When the voltage drops in the cap ( but at still dangerous levels) the resistor will reduce the needed current to keep the led lit thus giving you a false sence of security thinking the cap is discharged.....

for example lets say the LED you chose needs .030 A to be lit at full power and turns off at a minimum of .008A.

15KV NST can easily charge a cap to 21KV
21,000/.030 = 700Kohm resistor needed to keep led alive at 21KV (given that the resistor wont arc over)


.008X 700,000 = 5600 V   will still be in cap when LED turns off

and lets not forget that the cap can hold a charge that is reversed of what the LED may need ( since the cap is an AC style cap) and the LED wont even light up in this senerio.

Scot D



Tesla list wrote:

Original poster: "Dan" <DUllfig@xxxxxxxxxxxxx>

All:

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?

Dan