Replacing rectifier tube with diode...

Janis59

Joined Aug 21, 2017
1,863
RE""Nor diodes for 2KV"" + ""10A is too high""

1) Nowadays I see in the commercial technologic machines tube kenotrons still are in use when, for example, need to rectify 30 kV and 100 A at once. Indeed so drastic diodes I have never seen, but kenotrons may do the job. However, the question was about far lesser values.
2) Thats nothing genuine bad if have no any 2 kV diodes. In my youth in sixties, when first dides was invented as ultimate wonder, their serial soldering was counted a very extreme what obligatory must be accompanied by resistor matrix what unifies the voltage spread. Thus, as the first diodes permitted about 20 V only, the grid rectifier used 15 or 18 diode series, each paralelled with 100 kOhm resistor. Nowadays diodes have so much insignificant and uniform stable I(r) that there is no any need to use resistors. Even rectifier for 100 kV may be soldered by 100 pieces series of cheap 1A diodes 1N4007 or for higher frequencies at SMPS by UF4007. When I had to make 36 kV 5A Graetz bridge I used a enormous amount of 5x7 cm aluminium platelets mounted in a circle, each platelet kept the TO220 diode for 5A and 1 kV and from "pancake" both sides there blew two strong fans. Thermal camera explore shown the rectifier is trust-worth. Your case nothing of such extremes is needed, just put the 2 pieces 1N4007 in series and voila!
 

Janis59

Joined Aug 21, 2017
1,863
How does post #22 relate to repairing an older scope with a failed high voltage rectifier???
It shows the all four available alternatives and selects one what is best suited for this case.

There is nothing good to tell man "let go to the right". Only the benefit is if one tells him what bad will happen if he go left and what if he go straight, and tell what good will happen if he turn right. IMHO.
 

tonyStewart

Joined May 8, 2012
132
The Extra High Tension diodes exist. My bad on 1N400x . Pls forgive my slip.
If = 1A and Vpiv are not concurrent. ( if that wasn't obvious.)
 
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