DC bench power supply terminals - front panel terminals

Hi all. Anybody know whether there are official standards or unofficial standards for the ordering or arrangement of the front panel terminals for DC bench power supplies?

Many/most old-school power supplies have the order red, green, black (from left to right). Many supplies these days have it black, green, red (from left to right). I won't mention the vertical terminal arrangement in this post. Just the horizontal arrangements.

While order shouldn't actually matter when we clearly know what the terminals are, just wondering why many/most new-school supplies have gone down the road of black, green, red ----- different from old-school. The order of low voltage to high voltage to go with sign convention maybe? Or convenience of wire connections - such as if the black is on the left-hand-side, then the wire can go out to something like a breadboard (or those vertical supply posts on a full breadboard assembly) without needing to cross over other wires etc?

Mine is black green red. It's only a few years old.

I don't think there's any standard to it. I think it depends mostly on the manufacturer and where they decided to put things.

Delta_G: Mine is black green red. It's only a few years old.

I don't think there's any standard to it. I think it depends mostly on the manufacturer and where they decided to put things.

Cool. Thanks DG.

Didn't think too much about colours on this :frowning:

I should also mention - not necessarily about the colours themselves. But the order of the polarities.

Negative, Positive for many new-school bench supplies.

Positive, Negative for many old-school supplies.

I think keysight (aka agilent, aka hp, aka etc etc) still goes for positive, negative. Where-as tektronix have a mixed bag.

I thought I'd post this, only because I have DC supplies where some are pos neg, while others are neg pos. I'm guessing if for some reason we need consistency, can always open them up and physically change terminals around (and do some panel re-labeling).

Maybe has something to do with the number-line.

|500x64

.

larryd: Maybe has something to do with the number-line.

Hard to say, since keysight appears to have some consistency, while tektronix caters for lefties and righties. But certainly can't discount the number line possibility.

I guess one advantage of the - + arrangement is: If we have breadboard power terminals arranged in the classical vertical configuration like:

+

earth

Then having a (- earth +) arrangement at the DC power supply allows the power wires to approach the left-hand side of the breadboard without needing to cross-over. For neatness and convenience.

eg.

*- + * * * * * + ****-

Southpark: Hi all. Anybody know whether there are official standards or unofficial standards for the ordering or arrangement of the front panel terminals for DC bench power supplies?

Many/most old-school power supplies have the order red, green, black (from left to right). Many supplies these days have it black, green, red (from left to right). I won't mention the vertical terminal arrangement in this post. Just the horizontal arrangements.

While order shouldn't actually matter when we clearly know what the terminals are, just wondering why many/most new-school supplies have gone down the road of black, green, red ----- different from old-school. The order of low voltage to high voltage to go with sign convention maybe? Or convenience of wire connections - such as if the black is on the left-hand-side, then the wire can go out to something like a breadboard (or those vertical supply posts on a full breadboard assembly) without needing to cross over other wires etc?

I build my own power supplies. I use red for +5, yellow for +12, black for common, green for frame ground (NOT the same thing as common) and white for adjustable positive voltage.

I use 5-way binding posts, and place them 0.75 inches apart, center to center (that's the standard for multi-pin banana plugs).

Although most power supplies I've seen place the frame ground in the middle (that is, red, green, black). I prefer to place the frame ground at the end, since I rarely use it (that is, red, black, green).

One important thing is that the DC output MUST be isolated from anything on the line side (including frame ground). There should be an infinite ohms open circuit between ANY DC connector and ANY AC line connection (including ground).