TL082: TL082 is not working fine as subtractor

harikrishna metta

Part Number: TL082
Other Parts Discussed in Thread: OPA4171, TLV4171

WHY IS THIS OPAMP(TL082) NOT WORKING AS SUBTRACTOR (UNDER LOW DIFFERENTIAL INPUT & GAIN=1)? Application diagram is same as the diagram in the link. In the circuit, V2 range is 12Volt to 14Volt, V1 is 12Volt and R1=R2=Rf. And suggest an opamp that works in low differential input voltage. Thanks

over 5 years ago

0 kai klaas69 over 5 years ago

Guru 140200 points

Hi Harikrishna,

for me the circuit works beautifully:

harikrishna.TSC

Kai

0 Paul Goedeke over 5 years ago in reply to kai klaas69

TI__Mastermind 30600 points

Hi Harikrishna,

Can you provide some further information or data? What does "not working" mean? If you have scope shots and schematics, that would be helpful. The link that you provided doesn't work for me. If you use the "insert code, attach files and more..." link on the page, you can attach files right to the E2E post which is the best way to go.

Thanks,
Paul

0 Ron Michallick over 5 years ago

TI__Guru*** 140106 points

Hi Harikrishna,

Note that Kai [not Paul] used a dual supply, +/-15V. with a single supply, the output won't get close to zero.

0 harikrishna metta over 5 years ago in reply to Ron Michallick

Prodigy 20 points

you got my problem, my application must use single power supply, can you suggest any other IC. The problem is inherent with a single supply because of output transistors in opamp. Is there any method, someone must've tried to overcome this problem, i think!. The application is shown below, first opamp is providing +/- supply, 2nd and 3rd combined is an absolute circuit, last opamp is a subtractor, and i need the sustractor output with respect to GND, till zero.

0 kai klaas69 over 5 years ago in reply to harikrishna metta

Guru 140200 points

Hi Harikrishna,

you could take the TLV4171 or OPA4171. Both are output rail-to-rail OPAmps.

Kai

Amplifiers

Amplifiers forum

TL082: TL082 is not working fine as subtractor