"D. v. Bilt" wrote in message
...


It just crossed my mind. If a mosfet used in switch mode should or
could a thyristor also work. Do manufacturers make them already
for high frequencies ?
Because a power mosfet is far too expensive to hobby around with.

The main problem I see is the fact that they are generally designed to lock
into the on state, until the load current drops to zero. For a switch mode
power supply, the switching device has to be able to break full current. If
you used an SCR it would lock on, and things would melt under most
conditions.

The only switching circuits they can be used in is circuits that are
designed to drop to zero on it's own for the SCR to unlatch. Like AC load
control, where the sine wave drops to zero at a 120 times a second.

Like the old computer line printers. They had a bank of SCRs driving the
printing heads. The inductive rebound would bring the current to zero and
allow the SCR to unlatch after triggering. But If one stuck on, you better
shut the system down quick, or the thing was going to burst into flame.