Here are my 2 favorite power supplies. http://www.ko4bb.com/Test_Equipment/Power_Supplies.png
The one on the left is a 30V/3A supply. The current limit is adjustable with a 10 turns pot, so it can be precisely set. I only use 3 turns of the 10 turns pot, so that one turn is one A, resolution is 20mA. I find it extremely convenient to be able to precisely set the current limit without having to use another instrument. When in current limit, the lower LED turns on. It has a variable speed fan, so that while small, I can use it at any voltage/current setup, but it is only noisy when it's working hard. The transformer uses a dual C tape wound core, and while small, it occupies the vast majority of the space in the box, the rest being the filter cap. Ther electronics uses whatever space was left around those parts. The heat sink in on the back side, in the open, with the fan blowing across it. The meter can display V or I, and when you press the small push-button, the scale is 1/10th (0.3A FS). It is very low noise and stable, with a good voltage reference. It will also sink current at the programmed value, convenient to check batteries. It was completed about 10 years ago, but I have improved it since with a better reference, better op-amps and better compensation for better ripple/noise/transient response. The one on the right is an oldie, I started it while in college. People who were not yet born now have their own children going to school... It is a tracking, dual adjustable output supply, with a 10 turns pot to adjust the voltage in 2 ranges, 0-10 or 10-20V with about 0.5A max current. This one is not current limited, but it trips very fast and shuts down if the current is exceeded (it has very small output capacitance). I found that preferable when working on sensitive analog circuits. You can set it to 10V and connect it to the B-E junction of a small bipolar transistor without blowing it. It also has a third output, nominal 5V/0.5A that is adjustable in voltage or can be switched as a constant current output 0.05 to 0.5A) with the screwdriver type front panel potentiometer. It is also convenient to charge batteries. I also have a number of commercial supplies, by HP, Topward and Powermate, with higher voltage and/or current capability when needed, but these are the ones I use all the time. Both are pretty small, the big one is 16 x 7 cm (6.3"W x 2.75"H) across the front (the current fan is a little taller...) That's another reason I use them all the time. Didier KO4BB Internal Virus Database is out-of-date. Checked by AVG. Version: 7.5.519 / Virus Database: 269.22.5/1358 - Release Date: 4/3/2008 6:36 PM _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
