Can anyone suggest a supplier of domestic light switches suitable for 250 volts DIRECT CURRENT.
I asked this in the old forum, and IIRC a respected member suggested a supplier of “heritage looking” switches but these were in fact still AC only.
Have previously obtained NOS switches from fleabay but these are now hard to find.
Cannot directly help but you may be able to switch a pilot signal to operate a power transistor in a box, or even a relay, but they have a similar contact derating problem.
(there are many possibles, but just an example. would need a turn on resistor and Zener to protect the gate-source junction from blow-out.)
What is the load current and is the polarity fixed ?
I'd only use that for cases where if the transistor failed and it came on by accident it was not the end of the world.
The arc damage is a function of the current flowing and the breaking time the old DC switches had a very fast contact separation,
If you have both supply poles available you can even do the electronic equivalent of the big circuit breakers and have “load contacts” and “breaking contacts” where the breaking contacts are in parallel and only carry the load when the switch proper is opening, so no volts across it at the moment of opening.
Mike.
Cannot directly help but you may be able to switch a pilot signal to operate a power transistor in a box, or even a relay, but they have a similar contact derating problem.
(there are many possibles, but just an example. would need a turn on resistor and Zener to protect the gate-source junction from blow-out.)
What is the load current and is the polarity fixed ?
I'd only use that for cases where if the transistor failed and it came on by accident it was not the end of the world.
The arc damage is a function of the current flowing and the breaking time the old DC switches had a very fast contact separation,
If you have both supply poles available you can even do the electronic equivalent of the big circuit breakers and have “load contacts” and “breaking contacts” where the breaking contacts are in parallel and only carry the load when the switch proper is opening, so no volts across it at the moment of opening.
Mike.
