An amplifier circuit diagram consists of a signal pick-up transducer, followed by a small signal amplifier(s), a large signal amplifier, and an output transducer. Initially, there are two types of amplifier circuit diagrams is in practical i.e. voltage amplifier circuit and power amplifier circuit.
Voltage amplifier circuit | Amplifier Circuit Diagram
The primary function of the voltage amplifier circuit is to raise the voltage level of the signal. It is designed to achieve the largest possible gain. Only very little power can be drawn from the output. To achieve high voltage amplification, the voltage amplifier circuit must fulfill the following requirements.
- The transducer has a thin base i.e. the transistor with high
(exceeding 100) is used. - Input impedance is quite low in comparison to output impedance.
- Voltage amplifier always operates at low collector current nearly in order of 1mA because to permit high collector load, which is necessary to have high voltage gain.
- Mostly R-C couple is preferred for coupling various stages of voltage amplifier circuits because of its cheaper in cost and portability.
(exceeding 100) is used.Power amplifier Circuit | Amplifier Circuit Diagram
The power amplifier circuit is meant to raise the power level of the input signal. To get large power at the output, the input-signal voltage must be large. That is why, in an electronic system, a voltage amplifier circuit always precedes a power amplifier circuit, as shown in the block diagram of the amplifier circuit (Figure 1). This is why the power amplifier circuit is also called a large-signal amplifier circuit.
The region behind the power amplifier circuit called a large-signal amplifier circuit is because it draws power from a DC source connected in output and converts it into a suitable sine wave or AC signal. Power amplification is impossible because it is against the rule of physics. To achieve high power amplification, the circuit must fulfill the following requirements.
- In power amplification, heat is produced in the transistor during operation, so a large-sized power transistor as far as possible is used.
- A transistor having a thick base, not a voltage amplifier (smaller ) is used to handle the large currents.
- Mostly transformer-couple is used for impedance matching.
- Collector resistance made low.
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