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.
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
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- Â Electric guitar preamp circuit
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- 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) |
what’s input and impedance? this circuit works in guitar pickup with 3 single coil?