Op amp voltage follower unity gain amplifier circuit: Operational amplifier tutorial

Operational amplifiers (op amps) make great voltage followers! If you feed the output voltage directly to the inverting input (negative feedback), then the op amp will do a good job at holding the output voltage to whatever the voltage applied to the non inverting input is.

Operation amplifier 741 op amp voltage follower unity gain amplifier boosting trimpot signal voltage

Voltage follower using operational amplifier op amp unity gain amplifier circuit diagram by electronzap electronzapdotcom
Voltage follower using operational amplifier op amp unity gain amplifier circuit diagram by electronzap electronzapdotcom

Single supply op amp voltage follower

741 op amp follower using single supply power source

741 Op Amp Voltage Follower diagram by Electronzap Electronzapdotcom
741 Op Amp Voltage Follower diagram by Electronzap Electronzapdotcom

If more power (specifically, more current) is needed than the op amp output can provide, then a transistor wired as an emitter follower can be added to the output as shown in the video below. I wasn’t careful enough with the power handling capacity of the transistor after I replaced the LED with a 10Ω 10W resistor load. I probably fried a transistor experimenting between shots. So, don’t build any high power circuits based on this simple demonstration circuit.

741 op amp voltage follower output power improved with 2N2222 NPN bipolar junction transistor BJT

741 op amp voltage follower with 2N2222 NPN BJT transistor at output to increase power handling capability diagram by electronzap electronzapdotcom
741 op amp voltage follower with 2N2222 NPN BJT transistor at output to increase power handling capability diagram by electronzap electronzapdotcom


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