7815 not regulating.

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I have a 7815 fed 30V DC and it puts out 20V, not 15. Other parts do this, not just the first one I tried, so it's obviously something I am doing wrong. I have 2000uF before the regulator and 1000uF after. Is the capacitance too much after the regulator, or can I get away with that and the problem is something else altogether?
 
I have it feeding a OPA627 and I measured the voltage from the output of the regulator (which is tied to the +v of the opamp), oh, and this also aplies to the 7915, but I am gathering it was the same problem.

The GND pin is indeed connected to ground. And I did think it could have been the lack of loading, but I know not how much I have to load it to work. I don't want to fry my opamp with too much voltage if running it into a load isn't enough to bring down the voltage.

Could a simple resistive load connected across the capacitor after the regulator suffice? For the load from the opamp is going to be rather low. Or once I run the opamp into a load and it draws a little current you think I should be fine?

And I haven't tried to vary the input voltage
 
Well, this must be the most stupid thread in the history of this forum. I fixed the problem and I am so ashamed of what was causing the problem.

I changed the abttery in my multimeter and now the voltage reads 15V and -15V. Low batteries in my multimeter was the reason for this...
 
Not Alone

I have a habbit of needing one part but buying 10 or 20, never hurts to have extra right?

A couple of years ago I purchased (20) 7924 regulators from SAYAL electronics and guess what they all output -18v.

I ran over to radio shack and purchased one 7924 and when I put it in circuit... -24v

Tried to bring the bad 7924s back and was refused a refund or exchange, can't say I blame them but 20 bad regulators...:scratch:
 
JoeBob said:
Well, this must be the most stupid thread in the history of this forum. I fixed the problem and I am so ashamed of what was causing the problem.

I changed the abttery in my multimeter and now the voltage reads 15V and -15V. Low batteries in my multimeter was the reason for this...
Nothing to be ashamed of :no:

I have mesaured on circuits with the power supply switched off...... happens to all of us. :nod:
 
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