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I have implemented this circuit on my breadboard. The voltage waveform at point A and B in the circuit attached below should be equal because it's a voltage follower, but in my case, after implementing on the breadboard I am getting higher output voltage (Point B) than the input voltage (Point A). I have also attached the input waveform and the output waveform.

Can anyone tell me why this phenomenon is happening?

Circuit

Input voltage waveform

Output voltage waveform

Bread board image

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  • \$\begingroup\$ Why is the input signal so noisy? \$\endgroup\$ Jan 17, 2020 at 6:29
  • \$\begingroup\$ why is the signal so noisy? are you sure this is the right signal? are you sure the scope is on the right settings (no voltage magnifier for eg)? i suggest showing us your breadboard setup since this is such a simple circuit \$\endgroup\$
    – Andrew
    Jan 17, 2020 at 6:34
  • \$\begingroup\$ Are you sure you attached the probe(s) correctly? As other pointed out, signals are too noisy for a 1Vpp signal. \$\endgroup\$ Jan 17, 2020 at 6:39
  • \$\begingroup\$ I think the noisy signal because of the breadboard, and you can see the oscilloscope probes are connected correctly \$\endgroup\$
    – Ati
    Jan 17, 2020 at 7:00
  • 2
    \$\begingroup\$ Both Oscilloscope wires are connected at the same terminal. \$\endgroup\$ Jan 17, 2020 at 7:09

1 Answer 1

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The AD8606 is intended for a supply range from 2.7 volts to 5.5 volts and has a maximum supply voltage of 6 volts. According to your circuit, you are feeding it with +/- 3.5 volt supplies and this means the power supply is 7 volts: -

enter image description here

I'm not surprised that strange things may occur with such disregard for the data sheet.

You also indicate a 0.1 uF input capacitor yet, your breadboard shows an electrolytic AND, it appears that R1 is in series with the input signal instead of acting as a light pull-down: -

enter image description here

So, no bias on pin 3 and busting the absolute max ratings doesn't bode well for testing the AD8606.

I also don't see any supply decoupling capacitors. Typically 100 nF from each supply to GND are required for stable operation.

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  • \$\begingroup\$ Thank you for your reply. I have changed the supply voltage to +/- 2.7 and remove the resistor and capacitor at the input. now I just connect the input signal at pin 3 but the same problem I am facing. \$\endgroup\$
    – Ati
    Jan 17, 2020 at 10:16
  • \$\begingroup\$ Your device may be damaged now that you exceeded the AMR. Plus, if you have made circuit changes then edit your question with a new section (after the original parts) showing the new circuit and the new breadboard picture and please try and format the picture so it is in the correct orientation. \$\endgroup\$
    – Andy aka
    Jan 17, 2020 at 10:20

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