How to provide + and - to an opamp

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I continue to struggle with this

I think I can do it but I don't think I can do it with a single power supply I think I need two

I wanted to accomplish this before heading to work but all ive accomplished is connecting one output directly to ground

I was like dude just don't turn this on it's not gonna end well
I did briefly turn it in and increased the voltage output infinitesemally then turned it off
This pic is after the fact some stuff is disconnected
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I'm about to the point where I'm gonna make my own ground
Go outside and pound a rebar into the ground then run a lead into the house to my work area
I figured I could put the two outputs to work separately

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Kinda what I'm dealing with trying to use one power supply

Seems doable with two separate ones

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Now if I had an external or extra ground

Diagram one is still sketchy but way better

And diagram two looks better

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I was looking at a bipolar power supply on eBay not too bad less than $40 shipped goes up to 15V pos and negative
If I get it I can open it up and see how they did it

Anyhow in the meantime I have a power supply that has plus and minus 5V DC so I may see how that works
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I think I'm seeing that yellow may be a color to represent negative voltage

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Are the 2 Pos. outputs of the PACO completely independent of each other?

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Hello sir

I am gonna check with the meter but I think they are directly connected

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Also last night I went ahead and ordered one of these it was less than $40 shipped

Oh well I can't upload the pic but it's an R.S.R. electronics model 3010

So I can learn about this dual polarity stuff but also get on with some op-amp experiments

Edit: resistance between two outputs 0.7 ohm

[Kaz Kylheku]

So I can learn about this dual polarity stuff

I would say that forget about the schematic above for exploring dual supply; it is a single voltage supply. It produces one polarity, in two flavors: one output has less ripple because there is an inductor.

The simplest way to get dual supply is a center tapped transformer. Or use two completely separate transformers (I happen to own a piece of gear -- a 31 band rackmount EQ by AB International --- which is like that: two little trafos inside: one for +, one for -).

The center tap in the secondary windings of a transformer, or the point between two mechanically separate transformers, provides the ground reference between the two polarities.

The circuit you have there, although it has a center-tapped transformer, is not using the center tap for creating a dual voltage supply. It's using the center tap to have a 6V/12V switchable voltage. In the 12V mode, the center tap is disconnected and the full secondary winding is used. In the 6V mode, the coil is split, but the two halves of the coil are paralleled together in a way that they produce the same polarity.

Find a simple power supply schematic with a center tapped transformer, where there is no switch, and the center tap is used as the ground reference between the two voltages.

[Kaz Kylheku]

A simple way to provide dual supply is to use two identical batteries in series. The "center tap" between the batteries is ground. One battery then provides a positive rail, the other negative.

When you use two transformers, it's much the same. You can separately rectify them with separate rectifiers to get two DC lines, and then tie those together similarly to the batteries to get dual rail.

After that it's just optimization for space and fewer parts: using only one rectifier for both transformers, and merging the transformers together to a single one with a center-tapped secondary.