kzbin.info/www/bejne/ZpTFopWYbrWgiLssi=xTyFZMIoK6CDVA42

Google it.

Use the CT transformer and a bridge with two filter capacitors.

You can, if you are expecting a reasonably balanced loading between the positive and negative sides, use the center tap of the transformer as your ground reference. You'd have separate filtering and regulation for each side.

It's leading somewhere

Fine I'll be second then. Lol

OK, I just read up on the op amp subject. I forgot about that the voltage supply rail must be higher than the output voltage. So, not really a DC to DC convertor.

It's not a switching DC DC converter. It has a higher power source, 15V from outside. Its resistor feedback gives it a total gain of ~1.4 so it converts the ~7V of the zener to 10V at the output. Although you could say that most linear regulators are at their heart a little reference voltage (usually 1.25V), a simple opamp, and a pass transistor. Outside resistors set the gain of the opamp to drive the pass transistor so that you get your desired stablized voltage at the output of the regulator. Ofc extra circuitry gets put on the die for other features.

@@ivolol Thank you for the explanation! When I heard him say "boost the voltage," my whole understanding of power supplies became in question! I get it now, the high power source is the answer.

I think since the pot is used as a voltage divider its TC shouldn't matter much, however the other resistors in the feedback network should have a closely matched TC for good stability vs temperature.

@@victorman2227 One could use Vishay Low TCR SMD Thin Film Resistors, ± 2 ppm/°C, 0.01%, skip the potentiometer, and document the full burn-in reading, such as 10.083412 instead of 10.000000. Nothing wrong with having an non-integer calibrator. Also, using the highest precision OP Amp and skip the socketing. In multimeters, I noticed the LM399 is mounted a distance above the board, leaving longer leads, instead of creating any interruptions in the PCB substrate.

​@@pault6533 Yep, the only need for a round number is that it soothes the heart. For example in a piece of test equipment its possible to digitally store a constant of what the voltage is and not have to add any potentiometers. Another alternative way to adjust the output could be placing a number of resistors in parallel with increasing values, after measuring we can snip out the resistors that will change the voltage to the desired value. Higher value resistors will have a smaller impact on the resultant parallel resistance. I once made a 0.05% 5V supply to power an arduino doing some A-D in a power supply. It had to stay within 0.05% in 20-50C range (16 ppm/C max?). A discrete TC zener diode tested to 2ppm/C in 10C range (like the 1N821 but 9V) and OP07 opamp with wirewound resistors made a 10.xxxxV reference, which was then divided with a potentiometer to an accurate 5.000V which was the reference for a linear regulator. I didn't have a temperature chamber to check the tempco but after a day of the PSU being stressed at full load the voltage stayed within limits (it got rather hot inside). This is an order of magnitude lower than the precision that you are talking about though.

I always always at least round the corners. Man, I hate handling PCBs with square corners.

Yeah. Use it for fifty-some years at an ambient temp of 120C, using 120% of the maximum current. It will burn in and then burn out. After the burn out phase it will be the most stable device ever 😉

It's a single *point* ground where each conductor or wire arrives separately. So that the current on one circuit element doesn't affect the others. Same thing can be done for non-Grounds too, when you need (for example) a single point voltage reference. It's somewhat related to 4-wire measurements, so you can look that up for more explanation.

This is something that fascinates me, I'm on the search for the truth but what I have found so far suggests in favour of the pour ! and that's where my money is !

Besides what he said in the video you mean?

4 layer, everyone gets good grounds then