Voltage output for S7V8F5

I have a step up/down 5v regulator that has an input of ~6.6v and it is outputting ~6.8v instead of the 5v. Is there something about the behavior when the input voltage is close to the target?


Hi, Mark.

Could you post pictures of your setup that show all connections? Have you tested the regulator without anything attached to the output? What are you using to supply power?


Claire, thanks for the response. My circuit couldn’t be much simpler. It is just the 2123 with an input voltage.

I am measuring the voltages from the pictured breadboard leads. Input is 6.7v, the output is 6.9v. I have a 36v battery that is currently putting out 48v and is connected to this 5v regulator. The output of that regulator is the input to the 2123. The fact that it is outputting 6.7v is why I was looking to feed it through the 2123 to get it down to 5v (though I am looking into why it is putting out 6.7v to begin with).

I did another test, using 4 1.5v AA batteries for input. The input voltage is 8.08v and the output is 7.07v.

Do I just have a defective 2123?

It sounds like there are several weird things going on in your system. First, a 36V battery actually putting out 48V (even when fully charged) sounds suspicious to me. What kind of battery is it? Next, since neither of your regulators are behaving properly, I recommend troubleshooting them one at a time. How are you measuring voltages? If you have a battery-operated meter, try changing or charging your batteries before anything else. Hand-held multimeters can display incorrect values when their battery is low.


Hi Claire,

I think you nailed it. I replaced the battery in my multimeter, and now I am getting expected values. Regardless of what is going on with the 36v battery, I hooked my 4 AA batteries to the converter (5.9v) and it is converting to a solid 5v. I think it was my multimeter. Sorry for all the bother.


1 Like