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Good day! Today I want to bring to your attention the Laboratory Power Supply (LBP). I think every amateur radio enthusiast is faced with the problem of getting the necessary voltage for one or another of his homemade products, because each device requires a different voltage. I also encountered such a problem the other day. It was necessary to supply a home-made amplifier, but the necessary voltage was not at hand. Well, this is not my first homemade product with which I had problems. So I set to work.

And so, we need:
-Case (you can buy ready-made, but how can I take it from a computer power supply)
- A transformer with an output voltage of up to 30V and a current of up to 1.5 amperes (I took a more powerful trans as 1.5A is not enough for me)
-Simple set of radio components:
-Diode bridge on 3A.
- Electrolytic capacitor 50V 2200uF.
Ceramic capacitor at 0.1 microfarads (to smooth out the ripple more).
- Microcircuit LM317 (in my case 2 such microcircuits).
-Resistor variable 4.7kOhm.
- Resistor at 200th 0.5W.
Ceramic capacitor at 1uF.
-Old analog tester (I used as a voltmeter).
- Textolite and iron chlorine (for etching the board).
-Terminals.
-Wire.
-Soldering supplies.
Getting started! I took the case from the computer Power Supply. We disassemble it and pull out the insides and saw off the front panel (the one with which the wires come out) as in the photo.

Laboratory power supply


Next, we collect it back and cut out the front panel of the future power supply from the fiberboard, it will be more beautiful from plastic.

Laboratory power supply


We cut off the board mounting on one side and bend them in such a way as to fix the front panel made by us on them.

Laboratory power supply

Laboratory power supply


We select a place for the transformer, drill holes in the lower part of the housing and fix the transformer.

Laboratory power supply


Now we begin to collect the board to start it needs to be etched. We transfer the pre-printed circuit board to the textolite.

pay


And we throw in bleach for 10-20min. After etching, drill holes and tack on the board.

pay

drill holes


Solder the elements according to the scheme.

items on the board

block diagram

block diagram


We take the wires, assemble the circuit and pack everything in the case. IMPORTANT! (the microcircuit needs to be installed on the heatsink since under heavy loads it gets very hot and can fail). Here's what happened.

Laboratory power supply


Now you need to get the voltmeter from the old tester. To do this, simply cut off the indicator itself from the plastic case.

Laboratory power supply


Next, you need to put a jumper on the tester board in the 50V range, cut a hole in the front panel under our voltmeter and connect the wires. We isolate our board and close the case. I installed a cooler on top to blow the radiator on which the microcircuit is installed.

Laboratory power supply

scale

Laboratory power supply

Laboratory power supply


That's all! Laboratory power supply is ready! Good luck to all!
come back
Comments (9)
  1. igaz
    #1 igaz Guests October 11, 2015 23:14
    4
    This is anything but a laboratory power supply. Maximum supply for toys.
  2. TT
    #2 TT Guests December 31, 2015 19:06
    1
    You would have designed it with lamps, complete archaism, the 21st century, and you feel sorry for throwing out the old transformer from the TV set, shorting and burning everything.
  3. Apolonik
    #3 Apolonik Guests February 14, 2016 09:21
    0
    Yes, a little old-fashioned, and very simple. As they say, that which is simple is not forever. For beginner hams, what you need. Check every little thing. If we talk about a laboratory power supply unit, it is better to make it from LATR, the only thing you can’t joke with such a transformer is that you need strong knowledge as experiments can end tragically. I have everything.
  4. Sergey
    #4 Sergey Guests March 4, 2016 16:05
    0
    All this is good. But no offense, but heard about the LM350 and LM338, a digital voltmeter for example? And the build quality of the case is very sad. Although in general, the circuit is time-tested and is repeated at a time.
  5. Max
    #5 Max Guests August 5, 2016 01:19
    4
    [b] TT [/ b],
    But what does he short-circuit if his hands are not from a woman ... like some.
  6. Kai
    #6 Kai Guests December 13, 2016 16:21
    18
    There is nothing more reliable than a transformer-rectifier-stabilizer circuit, but old-fashioned, yes low efficiency, big dimensions, etc., but your favorite toy doesn’t flash like an impulse, you need more current, put a stabilizer more powerful, but in general, have one, and hait do not!
    1. Gts
      #7 Gts Guests May 27, 2018 16:51
      1
      For most amateur radio designs, a pulsed laboratory power supply, with a pulsed stabilizer, will do. For high output voltages and currents - size gain and savings on heat sinks will be very noticeable.
  7. Evgeniy
    #8 Evgeniy Guests March 2, 2019 9:27 p.m.
    1
    A completely suitable design for a beginner, simple and cheap, stability is also in order. Not everyone needs accuracy and stability of 1%. Well, heatsink should dissipate at least 30 watts. Well, and of course in the second scheme, turn it on two microcircuits cannot be, no two identical microcircuits. It is better to put a powerful transistor instead of the upper microcircuit.
  8. fcfc
    #9 fcfc Guests July 10, 2019 6:03 p.m.
    0
    fuflometsyn in one word

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