single supply operational amplifier negative voltage reference

[fjpompeo]

Dear sirs,

I need to build a negative voltage reference (commom VCC not GND) using a LM741, a zener and some resistors. Can you help me? Please take a look at the attached drawing it speaks for yourself. VCC=18Vdc~25Vdc. It will be used as a voltage reference in a negative rail regulated power supply so the positive rail goes from the smoothing capacitor to the output without regulation.

 

[crutschow]

What do you mean "negative voltage reference"? Do you mean 5V below the positive supply voltage? What is the value of VCC (V+)?

 

[kam1787]

how much current do you need supplied at 5V?

 

[udhay_cit]

So you need two different supply (with separate ground isolation). Yes you can give 5V supply in reverse polarity (Vcc grounded) to get the negative reference. I don't know the application of this circuit , but you can use some IC Chips like ICL7660