Power Supply Decoupling: Power Supply Decoupling - High-power amplifiers require high supply current levels, so unregulated power supplies are often employed to avoid the power wasted in a series regulator. The high ripple voltage that…
Output Current Limiting: Because the output transistors can be destroyed by excessive current flow, output current limiting circuits are often included in a power amplifier. Figure 18-27 shows the typical arrangement for a current limiting…
Quasi Complementary Output Stage: The Quasi Complementary Output Stage was originally developed because complementary high-power transistors were not readily available. Despite the fact that such transistors are now available, the Quasi Complementary Output Stage circuit…
Darlington Connected Output Transistors: High-power transistors usually have low current gains, so relatively large base currents must flow into Q2 and Q3 to supply a high load current. This means that the quiescent current through…
Direct Coupled Class AB Output Stage: The output capacitor in a capacitor-coupled power amplifier is a large expensive component that should be eliminated if possible. Figure 18-23 shows a Class-AB amplifier circuit with a Direct…
Capacitor Coupled Class AB Output Stage: The basic circuit of a Class-AB amplifier using a complementary emitter follower output stage and a Capacitor Coupled Class AB Output Stage load is shown in Fig. 18-18. The…
Complementary Emitter Follower Circuit: Two BJTs connected to function as Complementary Emitter Follower Circuit are shown in Fig. 18-17. Although one is npn and the other is prim the devices are selected to have similar…
Transformer Coupled Amplifier: Transformer Coupled Amplifier commences with the load resistance and output power, specification. A signal voltage amplitude may also be stated, as well as the upper and lower cutoff frequencies for the amplifier.…
Transformer Coupled Class B Amplifier: Class B Amplifier - The inefficiency of Class-A amplifiers is largely due to the transistor bias conditions. In a Class-B amplifier, the transistors are biased to cutoff, so that there…
Transformer Coupled Class A Amplifier: Class A Circuit - Instead of capacitor coupling, a Transformer Coupled Class A Amplifier may be used to ac couple amplifier stages while providing dc isolation between stages. The resistance…
