# Question: How Does A Transistor Control Current?

## Can a transistor be used as an amplifier?

A transistor acts as an amplifier by raising the strength of a weak signal.

The DC bias voltage applied to the emitter base junction, makes it remain in forward biased condition.

Thus a small input voltage results in a large output voltage, which shows that the transistor works as an amplifier..

## Can transistor be used as rectifier?

A transistor can be used as a rectifier. When you connect base-emitter or base-collector region and use it as a diode, a transistor can work as a low current rectifier.

## How are transistors controlled?

A voltage or current applied to one pair of the transistor’s terminals controls the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal.

## How is a transistor connected in a circuit?

To connect the transistor as a switch in a circuit, we connect the output of the device that will switch on the transistor to the base of the transistor. The emitter will connect to ground of the circuit. And the collector will connect to the load that the transistor will turn on and the supply voltage of the circuit.

## Why is VBE 0.7 V?

For an unbiased transistor, considering only the BE junction which is a pn junction diode, 0.7V is the potential barrier. In an npn transistor base is positive(p) and emitter is negative(n). … But in a pnp transistor the base is negative(n) and emitter is positive(p) so the vbe=-0.7V.

## Can a transistor amplify DC?

Yes,by using direct coupling(transistors) amplifier we will amplify low frequency (DC) signals. … A transistor is certainly capable of taking a small-current input signal and controlling a high-current output at the same voltage, thereby amplifying the power of the input signal whether it’s AC or DC.

## How many transistors are in a CPU?

The chip has 400,000 cores and contains 1.2 trillion transistors on a die over 46,000 square mm in area. That’s roughly the same as a square about 8.5 inches on each side.

## Which transistor is best for switching?

Best Transistors: BJTs#1 NPN – 2N3904. You can find most often NPN Transistors in low-side switch circuits. … #2 PNP – 2N3906. For high-side switch circuits, you need a PNP style BJT. … #3 Power – TIP120. … #4 N-Channel (Logic Level) – FQP30N06L.

## How does current flow in a transistor?

The NPN transistor is designed to pass electrons from the emitter to the collector (so conventional current flows from collector to emitter). … The base still controls current flow, but that current flows in the opposite direction — from emitter to collector.

## How does a transistor increase current?

The small current travels from the voltage source into the base of the transistor. A current at the base turns on the transistor. … During the negative alternation of the input signal, the transistor current increases because the input voltage aids the forward bias.

## What is transistor diagram?

Diagram ‘A’ shows an NPN transistor which is often used as a type of switch. A small current or voltage at the base allows a larger voltage to flow through the other two leads (from the collector to the emitter). The circuit shown in diagram B is based on an NPN transistor.

## What are the two main types of transistors?

Types of transistorThere are two types of standard (bipolar junction) transistors, NPN and PNP, with different circuit symbols as shown. … The leads are labelled base (B), collector (C) and emitter (E). … In addition to bipolar junction transistors, there are field-effect transistors which are usually referred to as FETs.More items…