# What is the meaning of input impedance?

The input impedance of an electrical network is the measure of the opposition to current flow (impedance), both static (resistance) and dynamic (reactance), into the load network being that is external to the electrical source.

Likewise, what does it mean to have a high input impedance?

A high impedance means that the circuit draws or provides little power on the signal. A low impedance means that the circuit draws or provides more power on the signal. Say the circuit under question (circuit B) is interfaced to circuit A on the input side and circuit C on the output side.

What does it mean to have high impedance?

In electronics, high impedance means that a point in a circuit (a node) allows a relatively small amount of current through, per unit of applied voltage at that point. High impedance inputs are preferred on measuring instruments such as voltmeters or oscilloscopes.

Why the input impedance of FET is so high?

Contrast this with the BJT. Hence, a BJT is current controlled , where as a n FET is voltage controlled. Naturally, you know that a reverse biased diode junction is like a open circuit, showing ideally infinite impedance. So, the reverse biased gate input of the FET is the cause of its high input impedance.

## Why emitter follower has high input impedance?

The emitter follower or common collector transistor configuration is widely used in many applications. The emitter follower or common collector circuit configuration acts as a buffer, presenting a high impedance to the circuit that is driving it, while offering a lower impedance output.

## What is the input impedance of a multimeter?

Impedance basics. Most digital multimeters sold today for testing industrial, electrical, and electronic systems have high impedance input circuits greater than 1 megohm. In simple terms this means that when the DMM is placed across a circuit for a measurement, it will have little impact on circuit performance.

## What is the input impedance of an oscilloscope?

Every oscilloscope will add a certain impedance to a circuit it’s reading, called the input impedance. Input impedances are generally represented as a large resistive impedance (>1 MΩ) in parallel ( ) with small capacitance (in the pF range).

## What is the source impedance?

The output impedance of an electrical network is the measure of the opposition to current flow (impedance), both static (resistance) and dynamic (reactance), into the load network being connected that is internal to the electrical source.

## What is input impedance in antenna?

Antenna impedance relates the voltage to the current at the input to the antenna. Let’s say an antenna has an impedance of 50 ohms. This means that if a sinusoidal voltage is applied at the antenna terminals with an amplitude of 1 Volt, then the current will have an amplitude of 1/50 = 0.02 Amps.

## What is the input impedance of an op amp?

it is found that the op amp input impedance for the circuit is at least the that between non-inverting and inverting inputs, which is typically 1 MΩ to 10 TΩ, plus the impedance of the path from the inverting input to ground i.e. R1 in parallel with R2.

## What is the input impedance of an amplifier?

Input Impedance, ZIN or Input Resistance as it is often called, is an important parameter in the design of a transistor amplifier and as such allows amplifiers to be characterized according to their effective input and output impedances as well as their power and current ratings.

## What is the meaning of load impedance?

The load impedance is the impedance you put on the output of the circuit (in this case the amplifier). In this case you can see almost no power is drawn this means that the output impedance has to bee very high. This means that you can connect a high input impedance amplifier on the output of the first amplifier.

## What is the early effect?

The Early effect, named after its discoverer James M. Early, is the variation in the effective width of the base in a bipolar junction transistor (BJT) due to a variation in the applied base-to-collector voltage.

## What is DB gain?

In electronics, gain is a measure of the ability of a two-port circuit (often an amplifier) to increase the power or amplitude of a signal from the input to the output port by adding energy converted from some power supply to the signal. It is often expressed using the logarithmic decibel (dB) units (“dB gain”).

## What is a high impedance fuel injector?

High-impedance injectors, also called saturated fuel injectors, are sent a 1–1-1/2-amp current signal to open, and that current stays on until the injector closes. Low-impedance injectors, also called peak-and-hold injectors, are sent a more powerful electrical signal, usually around 5–6 amps, to open.

## What is the input impedance of a transistor?

The high input impedance of the common-collector configuration matches high impedance sources. A crystal or ceramic microphone is one such high impedance source. The common-base arrangement is sometimes used in RF (radio frequency) circuits to match a low impedance source, for example, a 50 Ω coaxial cable feed.

## What is high output impedance?

A high impedance means that the circuit draws or provides little power on the signal. A low impedance means that the circuit draws or provides more power on the signal. Say the circuit under question (circuit B) is interfaced to circuit A on the input side and circuit C on the output side.

## What is the meaning of output impedance?

The output impedance is the ratio of change in output voltage to change in load current. The power supply output impedance depends on whether it is used as a voltage source which ideally has zero impedance, or as a current source which has infinite or very high impedance.

## What is a high impedance input?

In electronics, high impedance means that a point in a circuit (a node) allows a relatively small amount of current through, per unit of applied voltage at that point. High impedance inputs are preferred on measuring instruments such as voltmeters or oscilloscopes.

## What do you mean by high impedance state?

Definition. Hi-Z (or High-Z or high impedance) refers to an output signal state in which the signal is not being driven. The signal is left open, so that another output pin (e.g. elsewhere on a bus) can drive the signal or the signal level can be determined by a passive device (typically, a pull-up resistor). Synonyms.