# How can a transistor be used as a current source?

## How can a transistor be used as a current source?

The simple use of a transistor enables a far more effective current source to be made. The current source operates because of the fact that the collector current in a transistor circuit is Β times the base current.

Is a transistor a current source?

A transistor is a current controlled current source. The base current controls the collector current when in circuit.

What is a current source in a circuit?

A current source is an electronic circuit that delivers or absorbs an electric current which is independent of the voltage across it. A current source is the dual of a voltage source. The term current sink is sometimes used for sources fed from a negative voltage supply.

### How do you create a current source?

If you want to make the current source adjustable, you have 2 options. Being the load current is decided by the voltage or the resistance, you add a potentiometer to the voltage source or a potentiometer as the output resistor so that you can vary the current output.

What is current mirror in BJT?

A current mirror is a transistor circuit that regulates the current through a load resistance, the regulation point is set by a simple resistor adjustment. Transistors in a current mirror circuit must be maintained at the same temperature for precise operation.

What is an ideal current source?

An ideal current source is by definition a two-terminal element with the property that the current flowing through the device is specified at every instant in time. This current does not depend on the voltage across the source.

## What is the ideal current source?

How do you find equivalent current sources?

The process involves replacing the voltage source V in series with a resistor R with an equivalent network which has a current source I=VR I = V R in parallel with a resistor R. The current source is oriented such that the arrow points towards the positive terminal of the voltage source being replaced (see Figure 4).

How do you construct a current mirror circuit using a BJT?

The first trick to use bipolar junction transistor as a current mirror circuit is to construct an exponential voltage to current converter using the transistor. This is done by providing a voltage across the base-emitter junction of the BJT and the collector current is taken as an output.

### Why do we prefer current mirrors over current sources in IC’s?

An ideal current source has infinite output resistance and is a non-realistic device. A current mirror circuit (a practical current source, with very high output resistance) acts very nearly as an ideal current source.

What is the difference between ideal current source and real current source?

Types of Current Sources Current sources are active network elements that provide the same current to any load connected across it. The purpose of a voltage source provides current to a load rather than voltage. Ideal current sources are providing the exact same current to any resistance connected to it.

Can you convert current source to voltage source?

Source transformation: Current Source to Voltage Source We can replace a current source is in parallel with a resistor R by a voltage source vs in series with the SAME resistor R. V. Parallel Current Sources Parallel current sources simply add together, and can be simplified by a single current source.