How does a transistor control the flow of current?

How does a transistor control the flow of current?

By turning a small input current into a large output current, the transistor acts like an amplifier. But it also acts like a switch at the same time. When there is no current to the base, little or no current flows between the collector and the emitter. So the base current switches the whole transistor on and off.

What happens when a transistor is used as a switch?

One of the most common uses for transistors in an electronic circuit is as simple switches. In short, a transistor conducts current across the collector-emitter path only when a voltage is applied to the base. When no base voltage is present, the switch is off. When base voltage is present, the switch is on.

How do you connect a transistor as a switch 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.

When transistor operates as switch collector current is maximum at?

Example of NPN Transistor as a Switch We are going to see the output at the collector by varying the VI at two states that is 0 and 5V as shown in figure. From the above calculations, the maximum or peak value of the collector current in the circuit is 7.1mA when VCE is equal to zero.

How to use transistor as a switch with example circuits?

But the output of the AND gate is only 5 volts By using a transistor as a switch, we can drive 12v or even high voltage loads with a 5-volt digital logic signal We can also use these devices for faster switching and pulse width modulation control unlike traditional mechanical switches In this example, we use dc motor control through a switch.

How is a transistor used to control high current loads?

It’s designed for switching high-current loads. It has three connections, the base, the collector, and the emitter. The base is connected to the microcontroller’s output through a resistor. The high-current load (i.e. the motor or light) is attached to its power source, and then to the collector of the transistor.

How is a transistor used in a microcontroller?

The most common example you’ll see of this in a physical computing class is to use an output pin of a microcontroller to turn on a motor or other high current device. The output pins of a microcontroller can only produce a small amount of current and voltage. But when coupled with a transistor, they can control much more.

How is the base voltage of a transistor controlled?

The voltage on the base of the transistor doesn’t have to be controlled by a switch. You can use a potentiometer, connected as a voltage divider, to produce a changing control voltage for the transistor’s base.