Rf Amplifier Circuit Am Radio

The amplifier works well when it is connected to the rest.

Rf amplifier circuit am radio.

Transistor rf amplifier circuit. Trouble shooting an rf stage is fairly straight forward. 2 26 figure 2 19 is the schematic diagram of a typical rf amplifier that is used in an am radio receiver in figure 2 19 the input circuit is the antenna of the radio l1 a coil which forms part of an lc circuit which is tuned to the desired station by variable capacitor c1. The preamplifier circuit provides a gain higher than 10 in the lw and mw range.

An input amplifier for a fm radio receiver with rf selection 88 108 mhz has been designed in the radio project. It has about 25 db gain in the frequency rang 88 108 mhz. The working of the circuit is simple. Noise figure is about 7 db at resonant frequency.

Using a signal generator a modulated signal is applied to the antenna terminals and if the stage is working properly the amplified signal will appear in the plate circuit across the interstage transformer t 2 to be passed on the converter stage. The rf amplifier is one of the key areas of any superheterodyne radio receiver and its performance can govern many aspects of the performance of the receiver as a whole. The rf amplifier circuit and tuning is the first area of the radio receiver that the signal encounters when it enters the radio. Am fm radio frequency amplifier this am fm radio frequency amplifier is built with only a few components.

The particular circuit configuration used for an rf amplifier will depend upon how that amplifier is used. You can employ 1 4 watt resistors or even 1 2 watt resistors which are easier to manage. Which makes the project simple and direct. It is there to select the wanted frequency and reject some of the unwanted frequencies.

In the final part of this chapter you will be shown some typical rf amplifier circuits. A radio receiver always has an rf section which is a tunable circuit connected to the antenna terminals. The amplified signals are fed to antenna input of the am radio receiver for better reception. Figure 2 19 is the schematic diagram of a typical rf amplifier that is used in an am radio receiver.

L1 is wound on the same core as l2 which couples the input signal through c2 to the transistor q1. The circuit can also work for short wave sw range depending on the quality of practical implementation. Mirror frequency rejection is between 5 db to 9 db.