#1.5w stereo amplifier schematics driver#

The most important voltage is at the emitters of T4 and T5. Preset VR2 is used to adjust amplification and avoid direct coupling between transistor stages T2 through T5. The next stage is common-emitter amplifier comprising transistor T2. The FET stage in the amplifier section is used to give a high input impedance. This is necessary because human hearing follows a logarithmic response, in which a change in the output power by a factor of 10 is heard as a change by a factor of two. Since the gate terminal of FET T1 can be regarded as an open circuit, the input impedance of the circuit is equal to the value of VR1. The value of VR1 is specified as 1-megaohm.

The input signal is coupled to volume control VR1 via capacitor C1. In other words, the output stage takes power from a DC supply to boost the signal so it can drive a load. The power comes from the power supply, and the output signal appearing across the load should ideally be a replica of the input signal. The output stage usually has to drive a low-impedance load such as a loudspeaker.

#1.5w stereo amplifier schematics driver#

The driver stage is a buffer between the amplifier section and the output stage. The amplifier section provides most of the voltage gain. It is typical of most audio amplifiersalthough the circuit is somewhat different.ДЄ power amplifier contains audio input, amplifier, driver, output and power supply sections. The block diagram of the amplifier is shown in Fig. Here we put all the theory to work and present a simple power amplifier module that can be easily built with readily available components.