Comparing the AC sinusoidal componentofthe input and the AC componentof the output,we see that the CE transistor ircuit is a voltage amplifier by whichthe input is amplified by times.
An amplifier converts a low voltage or power into a higher voltage or power signal. Different types of amplifiers and different formats are available depending on the applications required.The high-voltage amplifiers, with bandwidth from DC to few MHz, allow getting at the output stage, voltages of several hundreds of volts. This is called High Voltage amplifiers.Power amplifiers, low frequency, a few MHz maximum, are generally used to stimulate inductive loads, and are driven in voltage or current as required. These amplifiers deliver a few hundred watts to several kilowatts in loads often with very low impedance.RF power amplifiers (RF) are amplifiers that convert a low power RF signal into a higher power signal.
In general, RF power amplifiers are used in ultrasonic applications to drive piezoelectric sensors, or UHF / VHF transmitter antennas.The main parameters of the amplifiers are gain, output power, bandwidth, power efficiency, linearity (low signal compression at rated power), adaptability to output impedance, and Heat dissipation.
Next: Biasing Up: ch4 Previous: DC operating point AC Signal Amplification. The common-emitter transistor circuit is commonly used for voltage amplification, as shown in the example below. Here we assume and,. The current and voltage on both input and output sides can be obtained either algebraically or graphically as shown below. MOS Amplifier Basics. Small-Signal Amplifier Design and Biasing. Maximum DC voltage Vdsmax, to avoid destroying the device. These limits are superimposed on the output characteristic in Figure 2-2. The Q-point must be selected to lie below the shaded region in the figure.