4. Inductance and Capacitance

Capacitance

Is measured in Farads F

Formula for calculating parallel capacitance

Inductance

Affects a DC circuit only when the circuit is first turned on, turned off, and when there is a change in the load resistance

Ballast

A common inductor found in a fluorescent light

Inductor

A coil that opposses any change in current flow "chokes"

Electromagnetic devices

Solenoid, motor, buzzer, and relay

Total series inductance formula

Total parallel inductive reactance

Effects of a capacitor in the DC circuit

1. Charge to a voltage equal to the source voltage 2.Since the dialectic is an insulator and the voltage potential across the capacitor is equal to the source, A charge capacitor ask like an open and will not allow current to flow in the circuit

Solid-state, time-delay relay

A time delay relay that uses a RC timing circuit(resistor capacitor)

electrostatic charge

Energy stored by a capacitor

Total series capacitive reactance formula

Inductive Reactance

Resistance provided by a inductor in a AC circuit

Inductance

Measured in Henry's H

In a power supply that converts a AC input to generate a DC output, a capacitor is commonly used to

Filter the rectifiers Pulsating DC output

Three types of capacitors

Non-polarized, polarized or electrolytic, variable

Electromagnetism

Concept of a magnetic field being formed around a conductor when current flows through

Capacitive Reactance

Apparent resistance to AC by a capacitor

Magnetic field

Invisible force around a wire that is created when current flows through it

Soleniod

Electromagnetic device that is used most often to produce a linear motion

Relay

Consist of switch contacts and coil

Inductance

The resistance to changes in current flow

Inductance

Since the standard unit for inductance is fairly large it is usually listed and Millihenrys

Electromagnetic field

Exists around a inductor, the strength of which is proportional to the steady-state of current level

Inductive reactance formula

Uses the letter f for frequency

Capacitance

Basic Unit of measure is Farad

Variable capacitors

Can be adjusted by turning a knob

Inside a capacitor

Two plates are separated by the dielectric

Electrolytic capacitors

Must be connected with respect to polarity

Dielectric

A non-conducting material between the plates of a capacitor

In a DC circuit

A capacitor blocks the current

Capacitive Reactance

Unit of measure is ohms

In a AC circuit, a higher frequency

Means a lower capacitive reactance

Capacitive Reactance

Apparent resistance in a capacitor

A short term Power Supply

A charged capacitor

The charge, discharge time of an RC timing circuit

Is 5 times the RC time constant

A RC timing circuit is often used

In time-delay relays to achieve the right time delay

Ballast

One of the components in a fluorescent light fixture is a type of inductor

A inductor can be added to a filter

To smooth out the ripple in power supply outputs

Rectifier

The device that converts AC voltage to pulsating DC

Capacitor

Device that stores electrical energy. C