Posted by Damir [ 213.202.68.166 ] on January 23, 2005 at 03:00:27:
In Reply to: Test Points posted by manualblock on January 22, 2005 at 21:10:15:
B+ is about 200V, anode voltage (between anode and ground) is about 110 V, cathode voltage (voltage drop through 2 red LED, between the cathode and ground) about 3,5V. Most of the voltage drop from B+=200V to the Ua=110V is through the upper mosfet, lower would drop maybe Uds~1,5V or so. Upper mosfet must be mounted on the small heatsink. Use termal-conductive insulation.
Voltage through "current set" resistor (~100 Ohms in the schematics, use trim-pot of 500 Ohms - 1k, from the most resistance to the lower resistance) by Ohms Law is U=R*I.
Be carefull, high voltages are dangerous. PS cap can be charged for a long time after switching off, use resistive bleeder. Last time I forgot this (270uF charged at 430V, nice electro-shock)...
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