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Need Help Converting DC Voltage

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eterry94

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I have a small CRT display and driver board that I have extracted from a broken camcorder. The driver board requires 4.75 volts DC for power. I don't have any way of providing this voltage from batteries, so I need a voltage regulator, or converter or a transformer that will output 4.75 volts. I would prefer that the input voltage of the converter/regulator be 12 VDC, but a lower or higher voltage is acceptable. Any help is appreciated.
 
No way of providing it from batteries? Use 4 AA rechargeable batteries.
 
Last edited:
No way of providing it from batteries? Use 4 AA rechargeable batteries.

I considered that option, although that would provide 4.8 volts. (assuming the AAs are the typical 1.2 volts each) I don't know if the extra 0.05 volts would damage the circuit or not. Thank you for your help. I will use the AAs if I can't get a converter.
 
.05? Not a chance that's gonna hurt anything.
Any variable linear voltage regulator will work if you want an exact voltage. But I'm going to hazard a guess that since it was a camcorder that board was powered directly off a battery pack anyways.
 
For .05 volts? Nooo, you'd never find a practical resistor for that. I'm relativly secure that he could use a fixed 5 volt regulator and be fine, but that's only if I were doing it and I wouldn't mind if I hurt it.
 
.05? Not a chance that's gonna hurt anything.
Any variable linear voltage regulator will work if you want an exact voltage. But I'm going to hazard a guess that since it was a camcorder that board was powered directly off a battery pack anyways.

Ok, thanks for your help. I'll go with the 4 AAs. Also, not that it matters, but the camcorder battery is actually 7.2 volts, it steps the voltage down for that board.
 
Steps it down to 4.75 volts though? That's just a weird voltage.
 
Steps it down to 4.75 volts though? That's just a weird voltage.

I have the service manual for the camcorder, which has diagrams of all the circuits. It shows the voltage on the cable supplying power to the board as being 4.75 volts. (see attached image)
 

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  • Handycam CRT Ribbon Cable Pinout.PNG
    Handycam CRT Ribbon Cable Pinout.PNG
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It's probably designed for a nominal voltage of 5V, 4.75 is 5 - 5%.

If you've measured 4.75V it's because the PSU is on the bottom end of the tolerance band.

The chances are your CRT will work fine from 4.5V to 5.5V.

I would recommend six NiMH AA cells plus a 5V low dropout regulator.

How much current does this thing use?
 
It's probably designed for a nominal voltage of 5V, 4.75 is 5 - 5%.

If you've measured 4.75V it's because the PSU is on the bottom end of the tolerance band.

The chances are your CRT will work fine from 4.5V to 5.5V.

I would recommend six NiMH AA cells plus a 5V low dropout regulator.

How much current does this thing use?

The circuit diagrams in the service manual said that the input on the CRT driver board is 4.75V. I was unable to measure what the actual voltage was because most of the camcorder had to be disassembled in order to get to the CRT and it's board. As for the current, I'm not sure, I haven't measure that yet. Thank you for your help.
 
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