Electrical Resonance - Research and rationale.

Azeem Mir

Electrical Resonance

Research and rationale

I have chosen to investigate the resonance in circuits after studying digging up the past and technology in space modules. Also my knowledge in electronics has been useful as it allowed me to understand the behavior of the apparatus, such as an oscilloscope, and the principles used in the investigation. I have used the physics principles for capacitance and inductance where the combined impedances cancel each other out or reinforce each other to produce a minimum or maximum impedance. Impedance is the alternating-current equivalent of resistance.

For my research I am going to look on the internet for any relevant information about resonance and the type of circuits it appears in. Also I will look back at the A-level physics textbook which contains the “Digging up the past” and “Technology in space” modules to refresh what I already learnt about resistance.

For each circuit, resonance occurs at a given frequency called the resonant frequency, which depends on the amounts of inductance and capacitance in the circuit. If an alternating voltage of the resonant frequency is applied to a circuit in which the capacitance and inductance are connected in series, the impedance of the circuit is a minimum, and the circuit conducts a maximum amount of current. If the capacitance and inductance are connected in parallel, the opposite occurs: the impedance is extremely high and little current will pass. [1]

Figure 1:Simple resonating circuit

Resonant circuits are used in electrical equipment, such as filters, to select or reject currents of specific frequencies. Filters in which either the capacitance or the inductance of the circuit can be varied are used to tune radio and television receivers to the frequency of the transmitting station so that the receiver will accept that frequency and reject others.

With an amplitude modulated (AM) radio the amplitude of the carrier frequency is modified so that it contains the sounds picked up by a microphone. This is the simplest form of radio transmission but is very susceptible to noise and interference. Frequency modulated (FM) radio solves many of the problems of AM radio but at the price of higher complexity in the system. In an FM system sounds are electronically transformed into small changes in the carrier frequency. The piece of equipment which performs the transformation is called a modulator and is used with the transmitter. In addition, a ...