input and output impedeance effects

[Bhuvanesh Nick]

"Low input impedence allows one to apply a weak current signal without decrease in its strenght.

High input impedence enables you to apply weak voltage signal without much change in it"


what this exactly mean...i nead an explaination..plzzzz

 

[peeyushsigma]

current follows the lowest resistance path ..that is why for a current amplifier, signal (current) to pass the input impedance must be as low as possible (ideally zero)..in the above figure as the value of Zin is decreased the current flowing through increases and the current amplification which is "Ai*current in Zin" also increases.



similarly in the volatage amplifier if the input resistance is high the voltage drop across it will also be high.. in the above figure as the value of Rin (input resistance ) increases the voltage across also increases and hence the voltage amplification.

 

[Bhuvanesh Nick]

View attachment 96302
current follows the lowest resistance path ..that is why for a current amplifier, signal (current) to pass the input impedance must be as low as possible (ideally zero)..in the above figure as the value of Zin is decreased the current flowing through increases and the current amplification which is "Ai*current in Zin" also increases.

View attachment 96303

similarly in the volatage amplifier if the input resistance is high the voltage drop across it will also be high.. in the above figure as the value of Rin (input resistance ) increases the voltage across also increases and hence the voltage amplification.

thank you so much for your help sir

i have poor knowledge in making equilent circuit.would you suggest me a place to learn that..

 

[peeyushsigma]

hello bhvanesh good to see your intentions...it is very easy to model a circuit ..first learn some basic standard circuits for a text book and try to analyse by doing so you will have an idea how to analyse the circuit ...follow any standard book of basic electronics ..you can follow "Electronic Devices and Circuit Theory by Robert L. Boylestad and Louis Nashelsky.

 

[Bhuvanesh Nick]

hello bhvanesh good to see your intentions...it is very easy to model a circuit ..first learn some basic standard circuits for a text book and try to analyse by doing so you will have an idea how to analyse the circuit ...follow any standard book of basic electronics ..you can follow "Electronic Devices and Circuit Theory by Robert L. Boylestad and Louis Nashelsky.

thanks if you dont mind may i have your facebook id or something else to contact..only if u not mind ..anyway once again thanks

 

[John Steave]

Input and output impedances, also called source and load impedances.It is steady and unchanging (ignoring the effect of the battery losing energy over time).
The output impedance, source impedance, or internal impedance of an electronic device is the opposition exhibited by its output terminals to an alternating current (AC) of a particular frequency as a result of resistance, inductance and capacitance. It is the Thévenin equivalent impedance looking back into the output terminals.
https://en.wikipedia.org/wiki/Output_impedance
Try to attempt you will have an idea how to analyse impedence effect and utilize **broken link removed** for your performance.

 

[peeyushsigma]

Input and output impedances, also called source and load impedances.

source impedance is the internal resistance of any source and Input impedance of any circuit is the impedance seen by the signal when applied to its input port

It is steady and unchanging (gnoring the effect of the battery losing energy over time).

input and output impedance heavily depend on the frequency of operation..