SCR regulated power supply

There is a schematic in the LT1083 datasheet where they use a thyristor to have the unregulated DC just a bit above the LDO. I didn't build the circuit yet and thus cannot comment on it. At

Rene

find

If you need theory and practice in one source, try looking at the GE SCR Manual, 4th edition. There's one on Amazon today for $8.99. Although it's almost 40 years old, the description of the SCR preregulator is very good. Of course, most of the specified parts are obsolete, but you can easily substitute if you know what you're doing.

Another good source is prior art. HP made a line of SCR pre-regulated linear power supplies back in the day. The operation manuals for these have schematics and theory of operation, and are a learning experience.

Please provide more information on your requirements to get a more specific answer.

Good luck Chris

SCR regulator is simple to build...

standard transformer and full wave bridge bridge feeds anode of SCR resistor from that point to gate ,with zener to ground.Zener sets output voltage. big capacitor from SCR cathode to ground.

I've used this 'bucket' regulator for over 30 years in various projects, never had any fail,even in telecom applications.

Values obviosly depend on curent and voltage requirements..... ..but it is a start...

good luck jay

find

if you can help yourself by giving more info, maybe. Meanwhile check out the Philips G8 tv power supply.

NT

output

projects,

Surely this would switch the scr on during the upswing of the supply half cycle, no? If so, the cap would then be charged to max unregulated. I get the feeling youre relying solely on transformer copper resitance to limit the charge delivered per cycle, which is why you say a big reservoir cap.

I suppose it should work though.

NT

If you do not yet know "What For" how will you know "Useful" when you find it?

I.E: Electric Drill, Vacuum Cleaner, Welding, maybe 240V, 50 Hz AC from 12 V DC (i.e. Mooring a Boat securely while providing power for the TeeVee).

voltage

Hi, Jay. Does this show the circuit you described above? (View in fixed font or M$ Notepad):

Sec .-------. 24VAC,10A | | SCR + o------. ,----o~ +o-------o---->|--------o----o 120VAC )|( | BR1 | | A \ K | )|( | | | \ | V(out) approx. 10V o------' '----o~ -o--. | G | | | | | | ___ | --- '-------' | '--|___|-o C --- | R | | | /-/ | | Vz=10V ^ | | | | - '-------------o-----o----o created by Andy´s ASCII-Circuit v1.24.140803 Beta

Thanks Chris

no......the zener only allows the SCR to turn on until the cathode voltage equals the zener's value( -.6 v of course).

and this circuit as simple as it is has worked for over 30 years, 24 7 as the saying goes.....

jay

Yes that's it....

Looks better than my 30 year old 'chicken tracts' on napkin !!

One day I'll have to learn how to do schematics quick and easy on a PC.......

jay