PPE Capacitors etc

Time constant

The time required for the current to rise (or fall) 63.2% of the maximum change possible.

Capacitive reactance

The opposition to current flow provided by a capacitor.

Formula for Capacitive reactance (Xc)

Xc = 1 / (2πfC)

Relationship between voltage and current in capacitors

Current leads the voltage by 90 degrees; ELI the ICE man.

Transformer

A device that couples electric energy from one circuit to another via a moving electromagnetic field.

Mutual inductance

Allows two electrically separate circuits to transfer power through mutual coupling of coils.

Primary winding of a transformer

The coil that is connected to the AC power supply.

Secondary winding of a transformer

The coil that is connected to the load where power is induced.

Power transformation in transformers

Power into an ideal transformer is equal to the power out; no power gain.

Step down transformer

Takes a high input voltage and reduces it to a lower voltage; Np > Ns.

Step up transformer

Takes a low input voltage and increases it to a higher voltage; Np < Ns.

Impedance matching

Process of matching the impedance of a supply to a load for efficient power transfer.

Power losses in transformers

Includes coil resistance, flux leakage, hysteresis loss, and eddy currents.

Coil resistance in transformers

Resistance that causes power loss as heat.

Flux leakage

When some of the magnetic flux goes through the air instead of the core.

Hysteresis loss

Heat produced when some magnetism is retained in the core during reversals.

Eddy currents

Currents induced in the core of the transformer that result in heat.

Ignition system

A device that ignites the fuel-air mixture in an engine.

Battery ignition

An ignition system that relies on an external power source like a battery.

Magneto ignition

A self-contained ignition system that does not require an external power source.

Spark plug

Creates an arc to ignite the fuel-air mixture in the cylinder.

Primary circuit in battery ignition

The circuit that generates a magnetic field used to induce voltage.

Secondary circuit in battery ignition

The circuit that delivers high voltage to the spark plug.

E-gap

The angle to open the primary points for maximum energy transfer to the secondary coil.

Persistent high voltage behavior

High voltage will find a path to complete the circuit, even through air.

High altitude flying problems

Thinner air provides less insulation, risking high voltage issues.

Distributor in ignition systems

Selects the proper cylinder to fire by directing current to the spark plug.