Definition of non-inverting amplifier circuit:

The signal is input from the non-inverting end of the op amp, and a part of the output signal is connected to the inverting input end of the op amp through the feedback resistor to form negative feedback. At the same time, the inverting end of the op amp is grounded through a resistor (or connected to a reference voltage, where the reference voltage is equal to half of the power supply voltage).

Characteristics of non-inverting amplifier circuit:

1. The input impedance is very high, at the megohm level. So for the amplification of small and weak signals, the non-inverting amplifier circuit is a good choice.

2. The output impedance is extremely small, a few ohms or more than ten ohms. Have a certain load capacity.

3. Voltage magnification. The voltage amplification factor of the non-inverting amplifier is equal to the resistance of the feedback resistance divided by the resistance of the grounding (or reference voltage) of the op amp's inverting end plus one.

4. The phase of the output signal is the same as the input signal.

The role of the non-inverting amplifier:

1. Used for the amplification of small signals. Since the non-inverting amplifier has a great input impedance, it can reproduce the signal source signal to the greatest extent. It also has a great magnification. The signal can be adjusted.

2. Used as a voltage follower. In the non-inverting amplifier, all the output voltage is fed back to the inverting input terminal to form a voltage follower. The output voltage at this time is exactly the same as the input voltage. It is similar to the common collector amplifier circuit (emitter follower) in the transistor amplifier circuit, but the performance is far better than the common collector amplifier circuit composed of transistors.

3. Used as an active filter. By connecting resistors, capacitors or inductors in series and parallel at the non-inverting end of the operational amplifier, an active filter can be formed to select a signal with a specific frequency required from a complex frequency signal.