Hi to all, simple question about my bench PSU

bigal_scorpio · Apr 19, 2008

Hi everyone,

Just a quicky that for once requires a simple yes or no answer!

I have an RS bench PSU that has 2 terminals that give a fixed 5v and 0v, and 3 terminals that provide a variable 0 to 15v+ a 0v and a 0 to 15v-.

I have used it for years and just come upon a circuit that would be easier to build if I could common both 0v connections on the breadboard, would this do any harm?

Thanks for looking.................Al

ericgibbs · Apr 19, 2008

bigal_scorpio said:
Hi everyone,

Just a quicky that for once requires a simple yes or no answer!

I have an RS bench PSU that has 2 terminals that give a fixed 5v and 0v, and 3 terminals that provide a variable 0 to 15v+ a 0v and a 0 to 15v-.

I have used it for years and just come upon a circuit that would be easier to build if I could common both 0v connections on the breadboard, would this do any harm?

Thanks for looking.................Al

No.

henrybot · Apr 19, 2008

ericgibbs said:
No.

I'll go ahead and screw up a simple thread... why not??

[EDIT] Ok... I thought you were telling him that it wasn't a good idea to do it. Then I read the reply again. My bad.

bigal_scorpio · Apr 19, 2008

Thanks Eric

Many thanks Eric, just wanted to be sure, so I didn't make that smoke the wife hates again! hehehehe

Regards............Al

picbits · Apr 19, 2008

If you really want to double check, bung a 100ma fuse between both 0v lines on the power supply and run it like that for a while - if the fuse blows then you know you probably can't.

Other thing to do would be to measure the continuity between both 0v posts and if its less than 1/2 ohm or so you should be fine.

Gut feeling would be you should be able to do it without any problems.

bigal_scorpio · Apr 19, 2008

Just tested resistance.

Other thing to do would be to measure the continuity between both 0v posts and if its less than 1/2 ohm or so you should be fine.

Gut feeling would be you should be able to do it without any problems.[/QUOTE]

Just tried the meter across both 0v terminals and there seems to be no direct connection at all even on the M ohm scale!

..........Al

Dean Huster · Apr 19, 2008

I would have assumed that the ground for the +5 was connected to the chassis (and earth ground if there's a grounded cord) and that the variable supply's common floated and that it was an option to connect the common to the chassis. Didn't the unit come with an instruction book and schematic? If not, can't you get one?

Dean

kchriste · Apr 19, 2008

Turn the power supply ON, set the +- variable to say 10V, and use your voltmeter to measure the voltage between the two 0V terminals. Do this on both the AC and DC ranges of the meter. If you measure next to nothing, it it safe to connect them together.

ericgibbs · Apr 19, 2008

henrybot said:
I'll go ahead and screw up a simple thread... why not??

[EDIT] Ok... I thought you were telling him that it wasn't a good idea to do it. Then I read the reply again. My bad.

hi Henry,
It it makes you feel any better, I also misread it.!
Had to quickly edit it from Yes to No.

ericgibbs · Apr 19, 2008

bigal_scorpio said:
Many thanks Eric, just wanted to be sure, so I didn't make that smoke the wife hates again! hehehehe

Regards............Al

Hi Al,
You said you wanted a 'Yes or No' answer... you didnt ask how to check it out.

In my experience where a bench top PSU has a separate 0V for the different voltage outputs,
they are usually isolated from each other.. [the 0V's that is]

And unless marked with a 'chassis' connection symbol, the 0V's are also ground free.
Its very easy to check this out using a DMM.

Dont forget to add a medium sized electrolytic, say 220uF and a 0.1uF at the connection point on your breadboard,
for each psu supply wire.

The type of smoke you want to avoid is the smoke with the 'dark brown smell'

bigal_scorpio · Apr 20, 2008

Power to the people!

Hi guys,

You were all right about the PSU being OK to common up.

Just tried it and it seems fine!

BTW I measured from all the posts and the only ones that had a PD between them were the ones that were supposed to, as Eric said.

Thanks for the input, yet another question successfully answered

Al

Hi to all, simple question about my bench PSU

bigal_scorpio

Active Member

ericgibbs

Well-Known Member

henrybot

New Member

bigal_scorpio

Active Member

picbits

Well-Known Member

bigal_scorpio

Active Member

Dean Huster

Well-Known Member

kchriste

New Member

ericgibbs

Well-Known Member

ericgibbs

Well-Known Member

bigal_scorpio

Active Member

Similar threads

Hi to all, simple question about my bench PSU

Active Member

Well-Known Member

New Member

Active Member

Well-Known Member

Active Member

Well-Known Member

New Member

Well-Known Member

Well-Known Member

Active Member

Similar threads

Privacy & Transparency

Privacy & Transparency