Various Power Supply Circuits
This page is somewhat incomplete but does provide a couple of Schematics of PS’s that I have been using for quite a number of years for one purpose or another.
The DC to DC power supplies offer an excellent supply of 24 to 30VDC either Positive or Negative outputs from a single + 13.8 VDC (typical Ham shack PS). The simplicity and cost is far better than purchasing Transformers and associated components to construct your typical Linear 24VDC PS.
A couple of the images show the PS’s that I am using except the heat sink is a simple piece of flat Aluminum 1/4″ thick & 3″ in length secured to the chassis wall of what ever I may be using it in. Not those shown.
I use the Positive version to power, or drive the many 24VDC relays I have in operation. The Negative PS is an excellent PS for the very common Microwave Bricks that use either a -19, or -20VDC input. Although this has NOT been a problem, you might consider placing an RMI shielding cover over the supply module. I have not done this and have noticed no birdies or interference of any kind.
Another application is Portable, and /or, Mobile use where something higher than 13 or 14VDC is required in either one, or both polarities.
A MUST DO: Make certain all relays have a reverse biased diode & 0.1uF Cap. across the coil to prevent back EMF from entering the regulators. A practice I usually make is to also place a forward biased diode in series with the line out from the regulators, perhaps a bit of over kill, but piece of mind is worth it.
Another note: remember to provide electrical isolation between active device and heat sink using adequate thermal compound.
Below are Images of Various Power Supplies:
i) DC to DC Positive
Schematic of Positive version.
ii) DC to DC8
Rather crude but very functional circuit for + version.
iii) DC to DC7
Another view of + version. NO heat sink installed.
iv) DC to DC2
v) DC to DC Neg
Schematic of Negative version
vi) DC to DC
Another crude but functional version of the Neg. PS
vi) DC to DC3
Side view of Neg. PS showing un-common heat sink. NOT recommended for service installation.
vii) 1071 case
Case description and pin out function of LT-1071, & LT-1070.
5 Amp & 2.5 Amp version respectively
Below is a Schematic for a Tetrode Screen & Grid Supply that has served ve1alq and many people very well for a number of years. The protection circuit while relatively simple provides excellent protection form over currents, etc