Single Transistor Current Amplifier
Category: Transistor Logic
Designer: RANA MUHAMMAD ADNAN KHALIL
Notes
This is a very basic and important circuit for understanding of npn transistor. In this circuit you will learn how a transistor is used to amplify the current. 1. The transistor can be used to amplify voltage signal and also for current signal. 2. In this circuit npn transistor (2n3904) is used in current amplifier mode. 3. Every transistor has its gain factor called beta and it vary from transistor to transistor but can be calculated by doing little experiment. 4. The beta of transistor can be calculated through this circuit. 5. The collector current (Ic) is beta times base current (Ib) Ic = beta * Ib 6. The emitter current (Ie) is the sum of both collector current and base current Ie = Ic + Ib 7. The beta of transistor is calculated by using this equation beta = Ic/Ib 8. These equations are verified through this simulation. 9. More gain can be achieved by adding more transistors, multi-transistor circuits will be added soon. Applications: 1. This can be used to measure the beta of transistor. 2. This circuit can be used to understand the working of a transistor. 3. This circuit is also used as current amplifier. 4. This circuit is also used to measure small current. Note: This circuit is designed and simulated in proteus 7.10.