Transmitter calibration

[BlkMax]

Can I use a 5VDC power supply out of an old computer as the power supply for calibrating pressure transmitters?

I would think that any 5VDC source would work.

I am going to be replacing my stock boost transmitter with one of the Honeywell units.

 

[Sledhead]

I'm not sure what the Honeywell draws but if it is an amp or less try a DC voltage regulator; cheap and small.

Google LM7805 voltage regulator.

 

[BlkMax]

Thanx, but I was thinking I have an old dead computer with a good power supply. This is just for the bench calibration.

 

[Sledhead]

This is just for the bench calibration.

Ahh, I was struggling with the extension cord issue :rofl:

 

[duratothemax]

The problem with computer power supplies is sometimes they dont output a steady voltage unless there is a specific load on them. And most of them are 5.5v instead of the 4.95-5.05v that the ECM outputs on its reference circuits. If you build a little smoothing circuit, a computer PSU works fine though.

Your best bet is to use either a 5v regulator such as an L7805 (you can get those at radio shack), or, my favorite is an LM2940t because its designed specifically for automotive applications and is much more rugged than the garden-variety 7805.

Make sure to add smoothing capacitors on the input/output because the LM2940 needs these to maintain a steady voltage output.

Then hook that little regulated circuit up to the +12v rail on the computer Power supply, not the 5.5v rail.

BTW you have a PM!

Ben