TRF radio receiver Basics | TRF radio circuit

This application note covers Tuned Radio Frequency receiver basics.It covers TRF radio circuit with explanation.

This TRF radio is used as improvement over basic crystal radio receiver. As shown in the figure, stages of amplification is added before and after the demodulator. This will improve the sensitivity of the tuned radio frequency receiver.

TRF radio receiver circuit

As shown in the figure, 3 stages of RF amplification is used between antenna and detector. This will increase amplitude of the received signal significantly. Two audio amplifiers are used after the detector, which introduce gain to operate loudspeaker efficiently.

When more than one resonant LC circuits tuned to same frequency are cascaded, overall selectivity is improved. The greater the stages, narrower the bandwidth and steeper are the skirts.

TRF receivers are widely used. In most of the circuits, Knob is provided in order to tune the capacitance. This in turn will change the resonant frequency.

Earlier days, separate knobs were provided for each of the tuned capacitors in cascaded stage. Later on provision for single knob changing all the capacitances has been incorporated in the TRF receiver circuit.

Radio Antenna Tuner Vs TV Antenna Tuner

Radio Antenna Tuner

Refer Radio Vs TV Antenna Tuner basics>> which describes Radio Antenna Tuner and TV Antenna Tuner.


RF and Wireless Terminologies