[Amps] 1N Diodes

[Adrian]

RM, said it best with ;

"Protection diodes should not be petite. Big, ugly diodes with a peak 
current rating of 200 A or more are best. I have seen smaller diodes - 
and the meter they were supposed to be protecting - literally blown away 
by a glitch. After some bitter experiences with lesser diodes, I began 
using the 1N5401. In small quantities, the 1N5401 costs about 20 cents 
each. It is rated at 200 A for 8.3 ms, 3 A rms, and 100 PIV. Other 
diodes from the 1N5400 family will work as well. During an extremely 
high current surge, a glitch-protection diode may short out - and, by so 
doing, still protect the precious parts. Replacing a shorted protection 
diode instead of a blown meter is almost fun.


To prevent the negative HV circuit from spiking to several kilovolts, 
connect a string of 200-A (or greater) glitch-protection diodes from the 
negative terminal on the high-voltage filter capacitor to chassis. Each 
diode will limit the voltage across itself to about 1.5 V. Typically, 
three diodes are needed - thus limiting the spike to about 4.5 V. The 
diode polarity is with the cathode band toward the negative high 
voltage. With one simple wiring change, the same string of diodes can 
also protect the grid-current meter and the anode-current meter."


vk4tux