Introduction to voltage follower circuit designed with LM11

This circuit uses an LM11 to form a 1G ohm input resistor voltage follower using standard built-in resistor values. With the input off, the input offset voltage is the same multiplied by a factor of R2, but the added error is small because the LM11 offset voltage is so low. This error will be reduced when the input source is connected to an ohm of no more than 1G. For AC coupled inputs a second 10M resistor can be connected in series with the inverting input bias current to almost completely eliminate the error, bypassing it will give minimal noise.
Characteristics of the voltage follower circuit:
The voltage follower is a common collector circuit, the signal is input from the base and the emitter is output, so it is also called an emitter output device. The base voltage and the collector voltage are in the same phase, that is, the input voltage and the output voltage are in the same phase. The main characteristics of this circuit are: high input resistance, low output resistance, and voltage gain of approximately 1, so it is called a voltage follower.
So what does voltage following do? In summary, the voltage follower plays the role of buffering, isolation, and improving load capacity.
The characteristics of the common collector circuit's high input impedance and low output impedance allow it to play an impedance matching role in the circuit, allowing the subsequent stage amplification circuit to work better. To give a typical application example: the signal output of an electric guitar is high-impedance. When connected to a recording device or speaker, adding this voltage follower before the tone processing circuit will make the impedance match and the tone more perfect. This circuit is used in the input section design of many electric guitar effectors.
The output voltage of the voltage isolator is similar to the input voltage amplitude, and is in a high-resistance state for the front-stage circuit and a low-resistance state for the subsequent-stage circuit, thus "isolating" the front- and rear-stage circuits.
Voltage followers are often used as intermediate stages to "isolate" the influence between the preceding and following stages. This is called a buffer stage. The basic principle is to utilize its characteristics of high input impedance and low output impedance.
The characteristics of a voltage follower with high input impedance and low output impedance can be understood in an extreme way. When the input impedance is very high, it is equivalent to an open circuit for the front-stage circuit; when the output impedance is very low, it is equivalent to an open circuit for the subsequent stage circuit. Constant voltage source, that is, the output voltage is not affected by the impedance of the subsequent circuit. A circuit that is equivalent to an open circuit to the front-stage circuit and whose output voltage is not affected by the impedance of the subsequent stage certainly has an isolation effect, even if the front-stage and subsequent stage circuits do not affect each other.