[Elecraft] Overvoltage Protector

[Scott Ellington]

Some power supplies, like the Samlex SEC 1235, have no built-in overvoltage protection.  All regulated power supplies are capable of producing much more than their normal output voltage if any one of a number of things fails.  Linear supplies are particularly susceptible, since the pass transistor can short.  

While Elecraft assures me that the K3 can survive an overvoltage with minimal damage, I prefer to be on the safe side.   So I designed a crowbar circuit, which can be used with any 12 V power supply up to 30A.  If the voltage exceeds the trip point (14-16 V), it will short the power supply output and, if necessary, blow a fuse.

http://www.ssec.wisc.edu/~scotte/hr/OVP.pdf

I haven't built this one yet, but a very similar one I built in 1984 worked fine.

73,

Scott  K9MA

Scott Ellington
Madison, Wisconsin
USA