06-06-2013, 11:59 AM
(05-06-2013, 03:53 PM)boiss Wrote: One thing that I thought VERY important was protection on these ccts. I provided Over voltage protection with diodes and/or SCR to ensure that the heaters would not be blown by a possible fault in the PSU. Valves from the 20s are hard to find and expensive.
Definitely! Failure in linear regulators is quite common. And when they fail, they nearly always fail short-circuit.
Using 800V FET's is a good idea, but unlike LM317's there is no temperature limiting if they overheat - such as if the screw holding them to a heatsink works loose.
