I was buildiing an amplifier circuit for +ve voltages only. When I used a 9V battery to supply V+ and V- (+ to V+, – to V-), I get a constant 8V at the output of the opamp. The output is not changing with respect to input. The circuit worked fine when I used a +/-12V dual power supply. However the way I understand it, using a single supply is okay as long as I'm not dealing with negative input voltages.
Electrical – How to supply an op-amp from a 9V Battery
amplifieroperational-amplifierpower supply
Related Solutions
You cant use AD8055 amplifier with single 5V supply because:
It needs at least 8V between + and - supply.
For LT1818 - im not sure where my red vertical line should be, please somebody confirm if I'm right or wrong.
In my opinion - this is "within the input common-mode voltage range":
Even if I'm wrong about "red vertical line" - this amplifier can't work with +0.5V signal at 0V at Vs- pin.
You can use the ICL7660. It takes a positive voltage (up to 12v) and generates the inverse:
Very easy to use, I've used it in several commercial products.
If the ICL7660 chip is difficult to find, you can also roll your own" charge pump inverter" using a 555 timer, which should be available anywhere, and a few extra components:
There are lots of variations on this circuit, not just for generating negative voltages but also voltage doublers and triplers too. Just do a Google search for "555 charge pump images".
Related Topic
- Dual power supply for Op Amp
- Electrical – Do signal input, signal output and dual supply ground reference connect together at some point
- Electronic – Why doesn’t ua741cn operate correctly with a single supply
- Electronic – How does one read the parameter “Voltage supply” for opamps at Digikey
- Electrical – Supply Voltages for Inverting Amplifier
- Electronic – Non-inverting op-amp saturating incorrectly
Best Answer
According to page 4 of the LM741 datasheet, the minimum supply voltage is +/- 10V, so powering it with +/-9V isn't guaranteed to work. The LM741 is a very old design, and its characteristics are not as good as modern op amps (that being said, it works fine, but it's not what I'd pick for a new design). I'd recommend getting a more modern op amp, you probably want one with rail to rail inputs and outputs as well as a lower minimum supply voltage. I've narrowed down the listing here, you still will want to make sure whatever you pick can use the supply you're planning to use.