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The input impedance of an electrical network is the measure of the opposition to current ( impedance ), both static ( resistance) and dynamic ( reactance ), into the load network that is external to the electrical source. The input admittance (1/impedance) is a measure of the load’s propensity to draw current.
How to calculate the output impedance of an amplifier?
The Output Impedance of an amplifier can be thought of as being the impedance (or resistance) that the load sees “looking back” into the amplifier when the input is zero. Working on the same principle as we did for the input impedance, the generalised formula for the output impedance can be given as: ZOUT = VCE/IC.
To minimize electrical losses, the output impedance of the signal should be insignificant in comparison to the input impedance of the network being connected, as the gain is equivalent to the ratio of the input impedance to the total impedance (input impedance + output impedance). In this case,
What does it mean to have no impedance matching?
We have no impedance matching (power matching), we use impedance bridging (voltage bridging), whereby the power amplifier often has an output impedance of only one hundredth of the speaker’s input impedance.
What happens to the reactive component of the impedance?
In this scenario, the reactive component of the input impedance cancels the reactive component of the output impedance at the source. The resulting equivalent circuit is purely resistive in nature, and there are no losses due to phase imbalance in the source or the load.
When to use high or low impedance in signal processing?
Signal processing. When a device whose input impedance could cause significant degradation of the signal is used, oftentimes a device with a high input impedance and a low output impedance is used minimise its effects. Voltage follower or impedance-matching transformers are often used for these effects.