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I'm having trouble when I'm trying to make a voltage-follower from GL324 opamp. I use the following data sheet:

http://www.datasheet-pdf.com/PDF/GL324-Datasheet-LGSemicon-558557

And following connections:

enter image description here

enter image description here

I use 12VDC as Vcc. And above is a photo from my setup. If I apply 9V as input there is no output. If I apply reverse voltage with the 9V battery, I see minus reading from the voltmeter. And the opamp gets very hot. I double checked my wiring and it matched the circuit schematics and datasheet.

What could be wrong?

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  • \$\begingroup\$ If you applied -9V from a single rail supply, you've probably fried it. \$\endgroup\$ – Tom Carpenter Apr 26 '16 at 22:25
  • \$\begingroup\$ @TomCarpenter Is the schematics right? So you are saying the opamp is broken? \$\endgroup\$ – user16307 Apr 26 '16 at 22:28
  • \$\begingroup\$ Schematics fine. Can't tell entirely from the picture but it looks wired up ok (unless there are loose connections). Have you probed the voltages on each pin to make sure they are correct? \$\endgroup\$ – Tom Carpenter Apr 26 '16 at 22:29
  • \$\begingroup\$ yes pin one and two (2 red in photo) are connected since they are inverting input and output. yellow one is pin three and it is the signal input. Two browns are GND and Vcc for the opamp. I checked many times. the jumper brown is output to the voltmeter. \$\endgroup\$ – user16307 Apr 26 '16 at 22:32
  • \$\begingroup\$ I can roughly see that, but have you probed each pin with the multimeter to check it is at the expected voltage - e.g. to detect broken wires, etc. I'd also try a different amplifier (there are 4 in the IC, so try one of the other 3). \$\endgroup\$ – Tom Carpenter Apr 26 '16 at 22:33
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It's been more years than I can remember since using breadboard but shouldn't the op-amp sit over the trough that runs horizontally through the middle: -

enter image description here

See also this to confirm: -

enter image description here

Ground power also needs to connect to the common connection for Vin and Vout.

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  • \$\begingroup\$ I think you are right since in my second try with another lm324 I inserted it in the middle and it worked. Probably pins were loose I didnt notice in the first way. It makes sense what you say.. \$\endgroup\$ – user16307 Apr 27 '16 at 7:38
  • \$\begingroup\$ You are a good learner! \$\endgroup\$ – Andy aka Apr 27 '16 at 7:39
  • \$\begingroup\$ the main point actually the pins are in the same line was totally wrong as you say. strange that no one noticed besides you.- \$\endgroup\$ – user16307 Apr 27 '16 at 7:41
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    \$\begingroup\$ As you get more experienced you tend to want to question everything lol \$\endgroup\$ – Andy aka Apr 27 '16 at 8:15
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Your problem is that your signal voltages and meters are not connected to power supplies, but are completely floating. What you need to do is

schematic

simulate this circuit – Schematic created using CircuitLab

As you showed it, the measurements and signals, having no connection to any reference point common to the op amp, are never going to make sense.

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  • \$\begingroup\$ 9V is my input signal Vcc is 12VDC. All grounds all connected. I dont think thats problem here. \$\endgroup\$ – user16307 Apr 26 '16 at 22:45
  • \$\begingroup\$ @user16307 - Then edit your schematic to show exactly how your circuit is connected. \$\endgroup\$ – WhatRoughBeast Apr 26 '16 at 23:13
  • \$\begingroup\$ I wrote in my question I use 12V u draw 9V Vcc \$\endgroup\$ – user16307 Apr 26 '16 at 23:16
  • \$\begingroup\$ @user16307, Your schematic shows nothing connected to the VCC and VEE pins of the op-amp. Please edit your schematic to show what you actually connected. For many of us, we can understand your circuit much more quickly by looking at your schematic than by reading your words. \$\endgroup\$ – The Photon Apr 26 '16 at 23:30
  • \$\begingroup\$ @ThePhoton I used another IC now on the breadboard. Thats the only photo remained.. But I think I figured out the problem. The opamp was defect definitely. I tried with another 324 another brand it worked. \$\endgroup\$ – user16307 Apr 26 '16 at 23:32

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