Operational Amplifier Fundamentals Unit 4 – The Voltage Follower
Exercise 1 – Voltage Follower DC Operation
EXERCISE OBJECTIVE
When you have completed this exercise, you will be able to operate a voltage follower using dc
voltages. You will verify your results with a multimeter.
EXERCISE DISCUSSION
- Voltage follower output voltage (VO) equals the input voltage (VI). Output voltage (VO) is
identical to the polarity of VI. - High input impedance reduces loading.
- Noise and stray pickup, which might develop across the high-impedance op-amp input are
reduced when input, impedance is lowered by an input resistor. - When output voltage (VO) is stable and the op amp is not saturated, differential input voltage
(VD) is intrinsically 0. - If VD is greater than 0V, the op amp saturates and cannot duplicate the input (VI).
- A change of input voltage (VI) causes a voltage to develop across the differential input of the
op amp. It responds by changing the output voltage (VO). Since VO is fed back to the input,
VO continues to affect VI until VD is restored to 0V; additional voltage change is then no
longer required, and the output voltage is stabilized at a new level.