dC TO dC CONVERTER

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Thread Starter

phil m

Hi all

I am looking for a simple way to convert a linear
0-10 volt dc input into a linear 0-5 volt dc output. Have basic knowledge of electronics (usually just enough to get myself in trouble) and would great;y appreciate any information

Thanks
 
J

James D Walsh

Look up 'potential dividers' in a practical electronics book, basically you need 2 resistors of equal value and then connect them in series.

You then want to take your supply off the connection point, which will be your 0-5 volts. You are just splitting the voltage in half.

Regards

James
 
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Steve Myres, PE

Depending upon the accuracy you require, the resistors-in-series dividing method may not be adequate, due to the resistance tolerance of the
resistors (typically +/-5%). In most applications it won't be a problem. If your application is that critical, you can hand pick the two resistors to have sufficiently matched values, or use a potentiometer as the dividing device instead and you can adjust the tap point
dynamically until it is just right.
 
M

Matt Warshawsky

These responses work great and are often also called voltage dividers. Just watch out that your input signal has enough power to drive your output other wise you will get a voltage drop or other problems. If your output requires
more current than your input you will have to use an Op-Amp or transistor setup (with the voltage divider) to supply the extra current.
 
As suggested by previous replies, the easiest solution is a potential divider. But you need to make sure the resistors you use in the divider are suitable for the input / output device impedances.

The resistances should be >> output (0-10V) impedance and the resistances should be << input (0-5V) impedance.

Not normally a problem with modern equipment, but if you have old gear it might be. Suggest you use resistors in range 1 - 10k.
 
M

Michael R. Batchelor

Just how simple? And what is providing the signal and where is it going. The easiest way to convert 0-10VDC signal (high impedance with minuscule current draw) to 0-5VDC signal (again high impedance with minuscule current draw) is just stick two equal size resistors in series, put the 0-10VDC on top, ground the other side, and pull 0-5VDC off the middle. You can probably do it for under one US dollar. But without a little more information about your application I'd caution that this might be *TOO* simple.
 
K
Depending on how much current the 0-10 V can supply and how little current the 0-5 V load demands, a simple voltage divider may do what you neeed. Use Ohm's law to calculate the currents and voltage drops. You'll probably want the current from the 0-10 V source to be at least 2 orders of magnitude greater than the 0-5 V load current for this to be workable. Otherwise, an active amplifier or buffer is needed, aka a signal retransmitter, voltage-voltage convertor, etc.

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Ken Irving
 
C
Two equal value resistors in series from the 0-10 volt source to ground. This gives 0-5 volts at the center. R values should be as low as practicable to miminize the effects of loading or, if the load is known the lower resistor can be calculated to accomodate it. I personally would add an opamp as a unity gain buffer or simply set the gain of a non-inverting opamp to .5, but those are a little complex without a diagram. Any opamp spec sheet from the usual suspects will show you typical circuits if the simple divider doesn't suffice. Use precision resistors.

Regards

cww
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