3.16 Filters Flashcards
What is a filter circuit?
A circuit designed to perform frequency selection by selectively filtering one frequency or a range of frequencies from a mix of different frequencies.
What are the three main functions of electronic filters?
- Allow certain electrical frequencies to pass through
- Block certain frequencies from passing through
- Completely block direct current electrical energy
What is a two-port network?
A circuit with an input port and an output port, often analyzed as a ‘black box’ with unknown contents.
What are the four different groups of filters?
- Low-pass Filters (LPF)
- High-pass Filters (HPF)
- Band-pass Filters (BPF)
- Band-stop Filters (BSF)
What is the series connection of a high-pass filter and a low-pass filter called?
Band-pass filter.
What is the parallel connection of a high-pass filter and a low-pass filter called?
Band-stop filter.
What is the principle of operation of low-pass filters?
They let low frequencies pass, including DC voltages, but block frequencies above the upper cut-off level.
What are the two basic kinds of circuits used for low-pass filters?
- Inductive low-pass filter
- Capacitive low-pass filter
How does an inductive low-pass filter work?
The inductor’s impedance increases with increasing frequency, blocking high-frequency signals.
How does a capacitive low-pass filter work?
The capacitor’s impedance decreases with increasing frequency, shorting out high-frequency signals.
What is the principle of operation of high-pass filters?
They let high frequencies pass but block frequencies below the lower cut-off level.
What are the two versions of high-pass filters?
- Inductive high-pass filter
- Capacitive high-pass filter
How does a capacitive high-pass filter work?
The capacitor’s impedance increases with decreasing frequency, blocking low-frequency signals.
How does an inductive high-pass filter work?
The inductor’s impedance decreases with decreasing frequency, shorting out low-frequency signals.
