RF/IF FILTERS/TRANSFORMERS

RF/IF FILTERS

These filters can be found in radio receivers and act a an Inductor, Capacitor and Transformer in one package.  These are specially designed tuned circuits.
The resonant frequency can be adjusted by tuning the coloured ferrite core.
In an ordinary radio, you will most often find 4 types of IF-cans. For the FM part the IF frequency is 10.7MHz.

The color of the slug in this CAN is most often pink. For the AM part the IF frequency is 455kHz.

RED - Oscillator. With 30pf - 300pf = 1MHz to 2MHz
YELLOW - First 455KHz IF filter transformer
WHITE - Second 455KHz IF filter transformer (not always used)
BLACK - Last 455KHz IF filter transformer

The can with the PINK color is a quadcoil for the FM demodulation.
This can is a LC unit tuned to 10.7MHz

Note the frequency of 455 or 10.7MHz.  Within this is the bandwith, which can be 150kH, 180kH ,220kH etc