How a transistor acts as an amplifier?

Answer 1

A transistor has three sections, an emitter, base, and collector. By extracting a small number of electrons from the base, a large # of electrons can flow across the transistor from the emitter, thru the circuit, and back to the collector.

Answer 2

Transistors, at least the typical bi-junction transistor, actually amplify current. We set them up in a voltage divider circuit that converts current gain into voltage gain.

The simple explanation is that a small delta current on base-emitter causes a larger delta current on collector-emitter. The gain is either hFe or collector resistance divided by emitter resistance, whichever is less.

Answer 3

There are three pins on a transistor. One is hooked to the input signal. One to the power supply, and the third to ground. (These have different names depending on whether the particular device in your hand is a bipolar transistor or a field-effect transistor.) The pin hooked to the input signal controls the amount of voltage allowed to pass from the power supply pin to the ground pin.

So, basically, to amplify an input signal you feed more power into the "power supply" pin on the transistor than you are feeding into the "input" pin.

You don't want a huge amount of difference between the input and output on a transistor because it'll distort if you ask it for much, so a really high-powered transistor amp has multiple stages. That's one large difference between designing a transistor amp and a tube amp: a tube will give you a lot more amplification in one stage before it distorts. Prime example: the Marshall 2203 amplifier head, which is the most popular heavy-metal guitar amp head around. It's a 100-watt amplifier that contains one stage of preamplification with two tubes and one power amplification stage with four tubes. If that was a transistor amp it'd have at least 50 transistors in it. Another example, and a better one at that, is the 4CX35000 radio tube...which will amplify a 1750-watt input to 35,000 watts in one stage. I love solid state devices for their low power consumption, reliability and low heat, but if you're looking for a lot of gain in very few devices, tubes have always been the way to go.

Answer 4

A transistor is a device that controls a large current with a small current. If it has an Hfe parameter of 50, then a 1 mA AC input current to it's base will cause a 50 mA AC current component at it's collector.

Answer 5

In a transistor, a small current in the base-emitter circuit stimulates a significantly larger current in the collector-emitter circuit by breaking down the barrier in internal diode junctions. External resistor networks may be used to regulate these currents and produce larger voltages from smaller ones.

Answer 6

As an amplifier, the amount of current a transistor conducts at any instant will vary in a manner which depends on the instantaneous value of the varying voltage that is applied to the base.

Answer 7

The red line goes down and the blue line just goes all the way up. Cool right?

Answer 8

A transistor does not act as an amplifier. It is used as a component in an amplifier circuit.

Answer 9

for amplify we use common collector biasing and take high input resistance and low output resistance