Transformer with central tap output waveform?

[mariush]

Something like that.

I'm attaching the design of a 50v 1A power supply below. You can see three relays there, each relay is always connected to a tap. depending on how the relays are on or off, windings are added.

Follow arc out 1 , arc out 2 and arc out 3 and you'll see somewhere lower on the page  a LM324 opamp powered from another transformer or pair of windings to have -5v and 8v.vref is a tl431 reference, usually 1.25v

note the capacitors after bridge rectifier in this schematic are incorrect, they say 5600uF 50v. In fact they should say 63v at least there.

[Dave]

Are you sure this is just a 1A supply? 2x 5600uF for 1A is ridiculous. The charging current pulses would be very large, likely stressing the transformer core.
What is the point of sense connections, that are not actually used for sensing the voltage, but are just connected in parallel with the main output?

[mariush]

Are you sure this is just a 1A supply? 2x 5600uF for 1A is ridiculous. The charging current pulses would be very large, likely stressing the transformer core.
What is the point of sense connections, that are not actually used for sensing the voltage, but are just connected in parallel with the main output?

You know, you're probably right about that. I apologize, I may have labeled it incorrectly. 

It's from a Circuit Specialists 3003x, so it's more likely it's a 30v , 3A power supply - after all the transformer windings don't add up to 50v and the two npn transistors/darlingtons should have alerted me that it's more than 1A - you don't usually need two of those for 1A.

Either way, it's still a relatively good example of how relays are used to switch between windings and how the relays are triggered.

I downloaded a bunch of schematics a while ago from their Circuit Specialists website store, back when they had datasheets listed for some power supplies of theirs. Nowadays, I'm not sure they have the schematics anymore.
I wouldn't be surprised if the schematics have some parts incorrectly printed, seems there's a lot of copy and past or at least reusing the same base pcbs between models. They all use the same icl7106 based voltage and current lcd displays for example...

I'm attaching a bunch of other designs I copied back then in case someone finds inspiration from them.

[carbon dude oxide]

Depending on the size of those capacitors after the bridge rectifier, you will get a relatively large initial pulse of current, could be up to 5-10 A. So your 200mA better be slow blow/delay fuse or you'll go through a few fuses.

so 24v rms ... after it's rectified it's 33.9v ... but don't forget you have voltage drops on the diodes, about 0.4-1v on each, so take out 0.8-2v ...and you're left with about 31v.  On low loads like I said the transformer will output more than 24v rms but at high load, it's gonna be more accurate, close to like this 24v ac rms.

I shall make it a time delay fuse now that you have said that ^.^

Also you said about the voltage drop acrross the diodes could i use shottky diodes to reduce the loss to under a volt?

Maby something like a couple of MBR1535CT shottky rectifyers?