Resonant Electronic Circuits

Peter Auer

Series and parallel resonant circuits

Source: allaboutcircuits,com

Capacitor

Inductor

Resonant Electronic Circuits

Peter Auer

Inductive and capacitive reactances

Source: electronics-tutorials

XC: hyperbolic decrease

XL: linear increase

Glossary:

reactance – Blindwiderstand

resonant frequency – Resonanzfrequenz

phasor - Zeiger

resonant frequency

fo

Soruce: HyperPhysics

Resonant Electronic Circuits

Peter Auer

Impedance

Source: HyperPhysics

Loss (Verlust)

Resonant Electronic Circuits

Peter Auer

Circuit quality and bandwidth

Series resonance

Glossary:

quality factor – Gütefaktor

bandwidth - Bandbreite

Quality factor

High Q – narrow bandwidth

Low Q – wide bandwidth

Resonant Electronic Circuits

Peter Auer

Source: HyperPhysics

Quality factor versus bandwidth in a parallel resonant circuit

              

Source: wikipedia

Bandwidth

Resonant Electronic Circuits

Peter Auer

Applications:

• Radio receiver and transmitter (amplifier, filter)

• RFID tags (Radio Frequency Identification)

• Medical therapy equipment

Resonant Electronic Circuits

Peter Auer

CLIL-tasks:

• Explain the function of a resonant circuit to a fellow student

• Explain the impedance versus frequency graphs

• Give an instruction for the lab experiment shown in the video

• Discuss the effect of the Q-factor on the bandwidth

Resonant Electronic Circuits

Peter Auer

• Gap filling text

A resonant circuit consists of a …………. and an ………………….

The frequency where XL and XC are equal in magnitude is called …………………

At the resonant frequency the impedance of a series resonant circuit is ………….

Bandwidth is calculated: ……………….. divided by …………….

The resonant frequency is determined by values of …………. and ………………

Resonant Electronic Circuits

Peter Auer

• Matching exercise

Find a matching pair of expressions:

minimal impedance narrow bandwidth

capacitive reactance series resonance

low Q parallel resonance

maximal impedance increase

inductive reactance wide bandwidth

high Q decrease