To gain access to revision questions, please sign up and log in.
- AS and A2:
- BJ Transistor
- Class A Amplifier
Also known as a Single Ended Amplifier
- C1 is the input coupling capacitor - it blocks DC voltages and passes AC.
- C2 is a decoupling capacitor. Frequencies above 5 Hz should be decoupled.
- R1, R2 and R3 are used to bias the MOSFET to get the correct DC potentials in the circuit.
- R4 is a load resistor.
- C3 is the output coupling capacitor. It passes AC to the speaker and blocks DC.
- The biasing should be adjusted to give a MOSFET drain potential of 6 Volts with no input audio.
- There is DC negative feedback to keep the biasing correct. The AC feedback is decoupled by C2.
- The drain current will be I = V / R = 6 / 10 = 0.6 Amps.
- The MOSFET and R1 will each dissipate P = I V = 0.6 x 6 = 3.6 Watts with no input signal.
- No cross over distortion - potentially better audio quality.
- Some audio enthusiasts believe this type of circuit is worthwhile in spite of its disadvantages.
- It's not energy efficient. 7.2 Watts of heat are produced even when there is no audio output.
A push pull amplifier dissipates almost no energy when there is no signal input.
- A bulky output coupling capacitor is needed.
- Large heat sinks are neeed to remove the waste heat.
Contacts, ©, Cookies, Data Protection and Disclaimers
Hosted at linode.com, London