Simple Preamplifier Circuit using Single Transistor

The project posted here is of simple preamplifier circuit and is the simplest possible. This circuit provides a voltage gain of about 3 to 30 and is dependent upon source and load impedance. The simple preamplifier circuit has low input impedance.

Description of Simple Preamplifier Circuit

The circuit of the simple preamplifier is designed using a single low power amplifier transistor and is configured in common emitter mode. The input signal is given to the base of transistor T1 through capacitor C1. Capacitor C1 is a coupling capacitor to couple the input signal to the base-to emitter terminals of the transistor.

simple preamplifier circuit using transistor

Vcc of 12V is given to the collector which serves the additional function of providing the base current. Under zero signal condition capacitor, C1 acts as an open circuit since the reactance of the capacitor is infinity at zero frequency. Thus, the capacitor C1 acts as a blocking capacitor. Similarly, capacitor C2 serves the same function. Thus capacitor C2 works as a coupling capacitor and feeds the amplified signal to constitute the output voltage.

The simple preamplifier circuit uses fixed bias. In this circuit, the zero signal operation may be established by selecting resistance R1.

Check out other preamplifier circuits posted in bestengineeringprojects.com

  1. Dynamic Microphone Preamplifier Circuit
  2.  JFET Op-Amp Based Stereo Control Preamp
  3.  Electric guitar preamp circuit
  4. Preamplifier for ceramic-pickup
  5. High-Gain Preamplifier Circuit Using Single Transistor

PARTS LIST OF SIMPLE PREAMPLIFIER CIRCUIT

Resistor (all ¼-watt, ± 5% Carbon)
R1 = 2.2 MΩ

R2 = 4.7 KΩ

Capacitors
C1, C2 = 10 µF, 10V (Electrolytic Capacitor)
Semiconductor
T1 = BC148B (low power silicon NPN amplifier transistor)

 

One Thought to “Simple Preamplifier Circuit using Single Transistor”

  1. tiago

    what’s input and impedance? this circuit works in guitar pickup with 3 single coil?

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