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What are the bias conditions base collector junctions for a transistor to operate as a switch?
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∙ 11y ago
Reverse bias
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∙ 11y ago
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What are the bias conditions of the base emitter and base collector junction for a transistor to operate as a switch?
In order for a transistor to operate as a switch, the base-emitter current must be greater than the collector-emitter current divided by a factor of hFe. In this state, the transistor operates in saturated mode, fully turning on.
What are the bias condition of the base emitter and base collector junction for a transistor to operate as a switch?
In order for a transistor to operate as a switch, the base-emitter current must be greater than the collector-emitter current divided by a factor of hFe. In this state, the transistor operates in saturated mode, fully turning on.
Do Transistor have a polarity?
Transistors have many characteristics and they most certainly require voltages to be a certain polarity if they are to work properly. There are two main types of transistor: PNP and NPN. They are identical except that all polarities are reversed on one compared to the other. There are many books and online resources that describe transistors but here is a very brief note about transistor operation. Each transistor has a base, a collector and an emitter. When a small current is passed from the base to the emitter, a larger current will pass from the collector the the emitter. With an NPN transistor, the base needs to be positive with respect to the emitter and the collector also has to be positive with respect to the emitter for the transistor to work. A PNP transistor is reversed, where both the base and the collector need to be negative with respect to the emitter to operate. Therefore, transistors do indeed have a polarity, even if it is more complex that some other devices. Disclaimer: The above description of transistor operation is greatly simplified and there are operational modes that are outside the conditions described. Please don't use the above description as a definitive guide to transistor behaviour.
Can you interchange the collector and emitter terminals in a transistor?
Yes, but the results will be quite unsatisfactory due to differences in the dopant profiles of the collector and emitter.In the normal connection, beta will usually be in the range of 20 to 150 and the transistor will operate at the frequency given in the databook. The same transistor with the collector and emitter interchanged, beta will usually be in the range of 3 to 10 and the transistor will be much slower than the frequency given in the databook. Other parameters will also be degraded below databook values.It should not in general damage the transistor though, but some transistors having very low emitter-base reverse breakdown voltage will have their emitter-base junction burned out when the emitter is used as the collector, in some circuits.
What are the bias conditions of the base-emitter and base-collector junction for a transistor to operate as an amplifier?
Normally the Emitter lead should be connected to a negative source, the collector to a positive source, and the base to a positive source. the condition is that the collector V should be the highest positive Voltage through the transistor for it to work properly.Now the thing to remember is that if a small amount of current flows through the base then large current will be transferred from the emitter to the collector. therefore it is recommended that the base has a potentiometer to allow you to variate the current to make sure you have the most efficient bias. Another Key thing that you should know is that the best voltage to bias a transistor at is directly between the forward break over voltage and saturation if you dont know these terms then look them up. otherwise those are the conditions for current magnification of a transistor
Does skeletal muscle have gap junctions?
No. It's the only type of muscle tissue that doesn't have gap junctions. Cardiac and smooth muscles have gap junctions.
Can two diodes connected back-to-back produce a transistor?
No, two diodes cannot function as a transistor.The emitter and collector of a transistor have different and very specific doping profiles to optimize them for their functions, diodes don't.The base is a very very thin layer that both allows current carriers injected by the emitter to pass thru the base and be collected by the collector, and allows the transistor to operate at high frequencies (early junction transistors, a type called grown junction, had thick bases and could not function above audio frequencies), the diodes are physically separated with a long metal wire connecting them.
How do you draw DC load line and determine the Q point?
we should be take two point from the the graph between collector current and emitter-collector voltage.. along the horizontal line collector current is zero and emitter-collector voltage become Vcc,and along the vertical line emitter-collector voltage is zero and collector current become Vcc/RL then by this line that drow between this two point is called load line that in this line the transistor allowed to operate....
What is the major difference an NPN transistor and a PNP transistor?
The NPN transistor has its conduction curve where the base is more positive than the emitter, while the collector is also more positive than the emitter. The PNP transistor is exactly opposite, with its conduction curve where the base is less positive than the emitter, while the collector is also less positive than the emitter.
What is description of Bc547 transistor?
BC547is an NPN bi-polar junction transistor. A transistor, stands for transfer of resistance, is commonly used to amplify current. A small current at its base controls a larger current at collector & emitter terminals.BC547is mainly used for amplification and switching purposes. It has a maximum current gain of 800. Its equivalent transistors are BC548 and BC549.The transistor terminals require a fixed DC voltage to operate in the desired region of its characteristic curves. This is known as the biasing. For amplification applications, the transistor is biased such that it is partly on for all input conditions. The input signal at base is amplified and taken at the emitter. BC547 is used in common emitter configuration for amplifiers. The voltage divider is the commonly used biasing mode. For switching applications, transistor is biased so that it remains fully on if there is a signal at its base. In the absence of base signal, it gets completely off.
Why NPN transistor are preffered?
You need a positive input to operate the transistor and since most circuits are negatively grounded when the transistor is not in use it has a negative input current thus using less power most of the time.
How transister work as amplifier?
A transistor works as am amplifier by virtue of the fact that you can control the current in one path with a smaller current in another path. In a typical class A (common emitter) configuration, a certain current from base to emitter will create a corresponding current from collector to emitter. Increasing or decreasing the base-emitter current will cause a corresponding increase or decrease in the collector-emitter current, by a ratio that is defined as hFe, or beta-gain. Of course, this means that you have to properly bias the transistor, and understand the nature of hFe. You can operate a transistor in cutoff mode or saturated mode if you exceed the hFe limits. Within the limits, a properly biased transistor exhibits a (generally) linear operation.
