Viewer Question: How Does A Single Supply OpAmp Work

Comments · 28

• WA

  @warrenking1815 · 3 years ago

  The output can be recovered by a capacitor connected to the output to block the dc component of the wave.

  5

• 4D

  @4DRC_ · 3 years ago (edited)

  To recover a nondistorted signal at the output you can:<br><br>1) Use a series blocking capacitor at the input <br><br>But this will add a high-pass filter effect to the amplifier. Which can be totally fine! But if you do need to avoid this (such as you need a strong low frequency, or quasi-DC response), you can:<br><br>2) Add vcc/2 dc bias to the input signal itself (or whatever DC difference exists between &apos;true&apos; 0v ground and virtual ground), by dialing up the internal DC bias of the signal generator. (Or down! If you&apos;re using a single negative supply and being freaky deaky like that!)<br><br>Or, if you have no control of the input source&apos;s internal DC level:<br><br>3) Raise the negative rail of the input signal by tying it to virtual ground, instead of real ground. You&apos;ll want to ensure the VG node can sink/source current at the desired frequency, so add some decoupling capacitance, or even better, use the extra op amp that&apos;s probably in the package as a voltage follower. ;)

  3

• PA

  @PappaBear_yt · 3 years ago

  Your videos are so informative and straight to the point. Thank you! 👍🏻👏🏻👏🏻💪🏻

  1

• IV

  @ivaranderson2556 · 2 years ago

  Well explained--thanks for sharing this

• WA

  @warrenking1815 · 3 years ago

  You can recover the output through a capacitor &nbsp;to remove the dc bias.

• DA

  @davidh1187 · 3 years ago

  So taking your second circuit, why was the output so &apos;rubbish&apos;? &nbsp;Experimenting in multisim I changed VCC to 4.5v, R3 to 5k and V2 to 1v and got a nice &apos;clean&apos; output. &nbsp;The voltage offset was not the expected 750mV from the divider (or even 7.5v in your example). &nbsp;Does one of your Op Amp videos explain this behaviour?

  3

• MR

  @MrGolam57 · 3 years ago

  am just learning about electronics and people talking about negative current does my head in what is negative voltage and how is it used ???

• LE

  @lezrekmohamed · 3 years ago

  Thanks for the educational video. I have made a 3005 lead 12 Marshall preamp. &nbsp;It works well with +17/-17 volts. I tried to make it work with a single power supply using biasing like you showed. It worked with Tl072 but heavily distorted. But didn&apos;t work with the original 1458 and JRC4558. What changes should I do to make it work.

• GE

  @Geoffs_ya_runkle · 3 years ago

  Thanks Paul. I like these simulations very much. I hope you are staying warm as that vortex descends on you. How did you come up with the value of the resistor at R1? I will go back and watch your back catalogue of opamp videos. Take care.

• QZ

  @qzorn4440 · 3 years ago

  wonderful op-amp video. &nbsp;😎 Do you have a simple? &nbsp; [ +/- 0 to10vdc input op-amp] &nbsp; {Vishay IL300 isolation optocoupler} &nbsp; [+/- 0 to 10 vdc output op-amp ] &nbsp; My simulated LTspice model does not agree with the real circuit. &nbsp;This is just for very slow analog tracking. &nbsp; Thank you.

• GE

  @generalleigh7387 · 2 years ago

  I can’t find an answer online- I’ve made a stage 3 gain stage fuzz module with single rail- when I engage it, it chokes out and fades in after about 1.5 seconds, what would cause this?

• WA

  @waynegram8907 · 3 years ago

  The Single Supply Opamp will CLIP the output waveform having a LOWER Headroom peak to peak voltage swing compared to using a Dual Supply Op amp has a HIGH output Headroom peak to peak voltage swing?