Before starting with the circuit diagram you should know the concept of npn transistor as a switch. Example of npn transistor as a switch consider the below example where base resistance r b 50 k ohm collector resistance r c 07k ohm v cc is 5v and the beta value is 125.
Low Side Vs High Side Transistor Switch Bald Engineer
Npn transistor as a switch circuit diagram. This is a schematic diagram for a circuit that uses an npn transistor as a switch that turns an led on or off. In an npn transistor current starts flowing from collector to emitter only when a minimum voltage of 07v is supplied to the base terminal. The areas of operation for a transistor switch are known as the saturation region and the cut off region. The transistor in which one p type material is placed between two n type materials is known as npn transistorthe npn transistor amplifies the weak signal enter into the base and produces strong amplify signals at the collector end. Npn transistor switching circuit. Look at this circuit component by.
The switch is on when the base is saturated so that collector current can flow without restriction. When the switch is closed a small current flows into the base b of the transistor. The transistor amplifies this small current to allow a larger current to flow through from its collector c to its emitter e. In npn transistor the direction of movement of an electron is from the emitter to collector region due to which the current constitutes. The small base current controls the larger collector current. The diagram shows the two current paths through a transistor.
The transistor is off when theres no bias voltage or when the bias voltage is less than 07 v. It is just enough to make led b glow dimly. If the circuit uses the bipolar transistor as a switch then the biasing of the transistor either npn or pnp is arranged to operate the transistor at both sides of the i v characteristics curves we have seen previously. At the base input a signal varying between 0 and 5v is given so we are going to see the output at the collector by varying the v i at two states that is 0 and 5v as.
Gallery of Npn Transistor As A Switch Circuit Diagram
