Tag Archive for control voltage

Back to the lab…

OK so I’ve enjoyed a bit of a respite from pretty much everything except relaxing and revelry as suits the season. I made sure and visited A1parts the other day and picked up some more parts and bits.

There, I was able to find two used transformers, one 25V CT and one (presumably) 28V one in a cool retro hammond case. I bought two since I figured I couldn’t lose by having an extra transformer about in that range, but also wanted to see how big the voltage jump would be after I rectified and filtered it. It was also a major piece of the puzzle for my control voltage board as it requires a separate supply from the main one to give an independent voltage reference as well as power my meters. The plan today is to test their output voltages and build up the basic control voltage circuit. I can then test the power drain of the 12V loads (relays and indicators) and their effect on the control voltages (hopefully minimal). This is probably the shortest path to finishing the next board in my power supply.

I realize I need to do up a new schematic for the cv board given the modifications I previously mentioned, and I will do that soon. I am just too eager to get my hands dirty and breadboard it up.

Other items I managed to grab while I was at A1:

  • Nice pair of side cutters
  • Panel nibbling tool
  • A collection of smaller gauge marettes
  • Some smaller gauge splice crimps
  • Some 0.1Ω 1% 2W resistors

The last item was a nice find and will be useful for experimentation. I could use them in my final design for the current shunts since the max power dissipated would be 900mW, and I may still, but I think I will shop on digikey for those precision current shunts I mentioned in a previous post. It would cut soldering down from 11 components to 2 components for the ammeter. Still, good enough for testing! I can parallel 10 of them to make 0.01Ω. Shame I couldn’t find the same in 10Ω to make the 1Ω shunt. I suppose I could put 10 of them in series but that’s just silly.