In the days of old, I used to use a mobile CB, which sat on a (designed for it) power supply. The CB was
12 volts DC, and the power supply rectified the house power, to provide DC for the two way radio. And the antenna was on the roof.
An old computer power supply with 12 volt output. Wonder if that would drive a CB mobile, or a CB walkie? Makes me wonder if I could wire a lighter socket to an old computer power supply and have a couple amps of 12 volt DC?
Anyone know how much 12 volt DC a power supply provides? On a survival note, maybe a 12 volt tap off computer power supply could charge up a car battery, or be emergency communications.
Depends on the supply, they vary a great deal. Use google to locate the specs on a supply. I doubt if most could supply
2 amps of 12V. You might consider a very small battery charger and a small battery (like a motorcycle batt). Look at the label on back of the cb to see how much current is needed. watts / 12 = amps required. If no label, check what amperage fuse the cb has.
That's because the supplies need a load on the 5 volt output. Hang a power resistor between 5V and gnd. some may also require a mometary short between two leads to start the supply.
Why reinvent the wheel? Rat shack used to sell a perfectly usable $20 bench supply that worked fine with CBs. Just checked, not anymore. Did a quick Google, and found several, that look like like modern versions of what RS used to sell- here is a likely loking example:
You had just received several replies that don't know what they are talking about.
The older computer supplies that were for the AT type computers work just fine for some 12 volt uses. Usually you need to put a small load on the 5 volt output. I sometimes just use an old hard drive. YOu have to look on the supply to see how much current you can draw out of the 12 volt side. All wires of the same voltage and poliarity hook together inside the supply.
For the ATX supply: Hook up a load to the 5 volt line. Old hard drive again.
Jumper pin 14 (PS-ON) to pin 13 (ground, black wire.) At this point, fan in PS should start spinning, drives should spin, and + 5/12v, -5/12v, +3.3v, and
+5vsb should be present at 20 pin connector.
Disconnecting pin 14-13 jumper should turn supply back off.
The supplies will put out from 5 to about 10 amps or more depending on the supply on the 12 volt wires, 20 or 30 amps on the 5 volt wires and not much on the minus voltage wires, look at the side and see if they list the current.
YOu may be able to open up the case and turn up the voltage some. Many mobile radios usually operate best around 13.8 volts as this is the nominal voltage of a running car. Also as they are switching supplies the may put out a signal on the frequency you are trying to receive. Short answer is you probably can run the CB on the supply, and yes if you do turn up the voltage. I use one to test some 2 meter ham radios when I don't want to hook them up to my regular DC supply. I did turn the voltage up some with the internal adjustment. Don't recall, but think that voltage pot is for all the voltages.
YOu probably can not charge a 12 volt battery as you must have some more voltage than 12.6 volts to charge the battery.
GEEZ! I wish more people understood electronics. Computer power supplies are very useful for many do it yourself projects and the fact that they are mass produced makes them very inexpensive for the experimenter. I wish they were around when I was a kid drooling over the the thought of having a high output regulated power supply for my Frankenstein like projects which I would recruit one of my little brothers to plug in while I ducked behind something. Here is a link to a site showing how to convert a computer power supply for bench top use:
Exactly. Last year a young licensed amateur friend and I dug through our old computer switching power supplies and then modified one for 12 volts around 15 - 20 amps (about 200+ watts).
Yes we had, in that case, to put a resistive load on the +5 volt output, comprising two 4 ohms ceramic resistors (because had plentiful supply of them) in parallel mounted on the metal case acting as the heat sink. i.e. 5/2 =3D 2.5 amps worked nicely.
At last report it was powering his ham rig without extraneous noise on amateur band frequencies; had thought at one point we might have to add another 'hash' filter to the 12 volt output, but not necessary.
Some of those discarded switching power supplies (probably operating internally up to 20 kilohertz) are quite powerful; up to 400 watts for example! And compared to 60 or 50 hertz 'analog' more compact and lighter. We have put another switching power supply, requiring fewer modifications on our boat as a battery charger. Adding a fuse in the
12 volt output lead. Input is 115v at 60 hertz when plugged into a dock.
I don't see why not. Twelve volts it twelve volts. I wouldn't think a CB radio would require any super regulation and computer power supplies are pretty clean.
They usually have a label on them giving their output. Here's an example
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But, even a super cheap one should be plenty to run a CB radio.
I don't see why you've become discouraged. It's really very simple to rig. You don't have to do the elaborated mods in that link -- you don't even have to open the case. Any one of the standard molex connectors has the voltages you need
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The yellow wire is 12v and either of the blacks are neutral/return/ground.
"jim evans" wrote in news: snipped-for-privacy@news7.newsguy.com:
Gotta have a -minimum load- on the +5 volt supply; that's what those PC supplies regulate by. Connecting an old hard drive will suffice.(you may also have to jumper a
+5v "sense" wire on the main motherboard connector to the +5v supply line;depends on the particular PC supply.)
Otherwise,the PC supply will "run away".[not good]
You are correct. Minimum 500ma load on the +5 required for stable voltage output on +12. I always just threw an old hard drive on when checking out a power supply (or trying to test a motherboard - MB alone in about 99% of cases was not enough load to start, and if it was, it was not enough load to regulate properly and half the time you didn;t get the required "power good" signal.
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