Need a negative voltage from a 0-60V power supply

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Discussion Overview

The discussion revolves around the challenge of obtaining a negative voltage from a 0-60V power supply to power a specific circuit involving op-amps. Participants explore methods for creating a split power supply configuration, including resistor dividers and voltage regulators.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant suggests connecting the (-) terminal to the -9V input and the (+) terminal to the +9V input, questioning the feasibility of using a resistor between -9V and -5V.
  • Another participant points out that the power supply configuration is unconventional and recommends setting the power supply to 18V to create a middle rail as ground and generate a -5V supply, noting that using a resistor divider may be possible under certain conditions.
  • A different participant proposes using an inverting voltage regulator as a straightforward solution for powering the op-amp.
  • One participant mentions that a two op-amp, single supply design could mitigate bias issues associated with the proposed configurations.

Areas of Agreement / Disagreement

Participants present multiple competing views on how to achieve the desired negative voltage, with no consensus reached on the best approach.

Contextual Notes

There are limitations regarding the assumptions made about the circuit's requirements and the specific configurations of the power supply that may affect the proposed solutions.

atlbraves49
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I will have to power the following circuit:

http://www.tekscan.com/images/flexi-circuit-new.jpg

I assume I can just hook the (-) terminal to the -9V input, the (+) terminal to the +9V input, set the power supply to 9V, and then toss a resistor between the -9V and the -5V?

Would that work? And what value resistor would i need between the -9V and -5V?
 
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First, on your figure, you should show the top opamp power supply pin as +9V and the bottom supply pin as -9V. The way you have them now is unconventional.

Second, I think you mean to say that you will set your 0-60V single power supply to 18V, and you want to know the best way to make a middle rail be ground, as well as make a -5V supply. This is discussed a bit in your other thread, I believe. Turning a single supply into split supplies is not a great option, but can be done if the impedances and powers involved lend themselves to a resistor divider with adequate capacitor decoupling.
 
Since your only powering an op amp, just use an inverting voltage regulator. I actually just finished hooking one up to an instrumentation amp a couple hours ago.
 
altbraves, a two opamp, single supply design would get around this bias issue.
 

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