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So as opposed to a BJT transistor (which has a large but measurable input impedance) a Mosfet has even larger (presumably infinite) impedance. The reason is because of a small non-conducting zone that exists between the Gate side and the Drain-Source side. It acts as a small capacitor (which capacitors have infinite resistance), and the electromagnet field produced is what drives current between Source and Drain. Now, why is this desirable? In the case of BJT's there is a small current that flows into the base, essentially drawing small but existent power from the circuit connected at the Base. It is more ideal to have a transistor that completely separates the current of the control circuit and the current in the circuit being switched/supplied. Simply, it means its more efficient. When BJT transistors are turned off, power is still being used. The same isn't necessarily true for Mosfet transistors.
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What are the Advantage of mosfet over fet?
MOSFET has high input impedance and offer input signal isolation from the circuit
In modern electronic multimeter a fet or mosfet is preferred over bjt because?
Because of its much higher input impedance. When measuring voltage, that makes the voltmeter appear to the circuit as if it's not there, so the presence of the voltmeter doesn't change the operation of the circuit.
What is the input impedance of an ideal voltage op-amp?
To get all the voltage from a source to a target without loss you need voltage bridging, that is a relative low output impedance to a higher input impedance. Usualy the input impedance is more than ten times higher then the output impedance.An input impedance is called also a load impedance or an external impedance.An output impedance is called also a source impedance or an internal impedance.
What is input and output impedance?
To get all the voltage from a source to a target without loss you need voltage bridging, that is a relative low output impedance to a higher input impedance. Usualy the input impedance is more than ten times higher then the output impedance.An input impedance is called also a load impedance or an external impedance.An output impedance is called also a source impedance or an internal impedance.
How do you get input impedance and output impedence of op amp?
Scroll down to related links and look at "Measurement of input impedance and output impedance".
What are the Advantage of mosfet over fet?
MOSFET has high input impedance and offer input signal isolation from the circuit
How a transistor behave as amplifier.What actually happen internally?
MOSFET has high input impedance in comparisson with JFET due to the insulation material of silicon dioxide
In a multistage amplifier input impedance is high and output impedance is low justify the statement?
no. input impedance is low & output impedance is high
Compared to bipolars FETs have-a high input impedance b low input impedance c same input impedance?
FET s have very high input impedance when compared with Bipolar transistors.
Why mosfet has insulated gate?
The SiO2 layer acts as an insulator and also it provides high input impedance to the MOSFET. This insulation is needed so that a circuit with high EMI or loads which generate back emf (motors) can be driven by applying gate current from a common circuit.
Which is better high input impedance or low input impedance and why?
That depends on the output impedance. In electronic we use voltage bridging, that is a relative low output impedance to a higher input impedance. Usualy the input impedance is more than ten times higher then the output impedance. An input impedance is called also a load impedance or an external impedance. An output impedance is called also a source impedance or an internal impedance.
Why is JFET used as an input device?
it has high input impedance
Why emitter follower preferred to transforms as a impedance matching?
because it has high input impedance and low output impedance
Why the input resistance of opamp is high?
Because op amp consist differential amplifier and they posses high input impedance so that op-amp also posses high input impedance.
Why a high input impedance?
A circuit (an amplifier) typically has a high input impedance so that it does not unduly load the input circuit. Any such load could cause distortion, and that is generally not desired.
What are the main differences between FETs and BJTs in terms of input impedance?
FET has very high input impedanceBJT has very low input impedance
Does a Digital Voltmeter have a high or low input impedance?
Digital voltmeter has high input impedence.
