15V power supply calibration ELVIS circuits trainer

[Justin.e.snodgrass]

Is there a way to adjust the voltage from the +15V power supply? I'm getting 15.5V and would like to adjust it back down to 15.0.

[SnowMule]

Are you reading that with no-load? 

Throw something at it to load it down a bit then take a measurement.  Regulators usually need some load (more than the meg- and gig-ohm Z that most meters present). 

[Justin.e.snodgrass]

Yes, the power supply has a load. There are numerous series/parallel circuits that the students build and measure voltages and currents.

[REDS · Accepted solution]

Hello Justin,

If you look at the specifications for the ELVIS, on page 10, you see that we specify the +15 V power supply with an uncertainty of ±5%, so it’s expected for your power supply to go from 14.25 V to 15.75 V.

That being said, as this is a fixed power supply, there is no way to bring the voltage down from 15.5 V to 15 V without using external circuitry. Please reference this thread for further information. I think using an OpAmp will be the best solution for you. For your convenience, I found the circuit you want to make on this datasheet, page 7, which is a Non-Inverting DC Gain amplifier. Because the ELVIS already has a breadboard, the implementation should be really straight forward.