zero-span

[seymahos]

hi,all my friends.
i want to convert 0-12vdc to 0-5vdc.i invite you; everyone who knows about this problem.i will happy to hear his explanations.
please guide me.

 

[Jattie]

Use a simple voltage divider using two resistors.

|------ 0-12V
< R1
>
|
|------ 0-5V
< R2
>
|------- 0V

Using the e24 series (I think) you can use 1k2 for R1 and 1Kfor R2. You'll have to play around with your math to get values that is closer to real world values. becuase R1 should be 1k4. Using carbon resistors you can &quot;calibrate&quot; the resistor by clipping a multimeter across the ends and taking a file and filing away some of the carbon and the value of the resistor will increase giving you and axact voltage devider. If this is for mass production you have to come up with better resitor values for the divider. As an alternative use a pot and one resistor around the suggested values and build your divider.

 

[nbucska]

Is it signal(analog, TTL ?) or power( Current? ) ? <nbucska@pcperipherals.com>

 

[melone]

What is this for?

 

[peebee]

Jattie's circuit would work for a signal circuit to drive some downstream high-impedance input device but would not work for a low impedance device or for a power circuit.

 

[ve7brz]

If this is a power circuit you'll need to use a DC/DC converter, or if the load isn't too great and efficiency isn't an issue then use brute force - a 5 V regulator.

If it's a signal into a high impedance input then use a voltage divider as Jattie suggested. If it's into a low impedance input then use the voltage divider followed by a single-supply Op-Amp configured as a voltage follower. In this case power the Op-Amp from the 12 V supply.