electric circuits

Power

The energy transferred per second, measured in Watts where 1W = 1 Joule per second.

Power Equation

Power(W) = Voltage(V) * Current(A)

Energy Equation

Energy(J) = Power(W) × Time(s)

Series Circuit

Equal current everywhere in the circuit; voltage is shared between components but must add to the voltage from the power source.

Parallel Circuit

Current is shared between components but must add to the current from the power source; equal voltage across each component.

Ammeter

Device used to measure current, which must be connected in series.

Voltmeter

Device used to measure voltage, which must be connected in parallel.

Resistance Calculation

Resistance can be calculated using the equation: Resistance(Ω) = Voltage(V) / Current(A)

Series Resistance Addition

When you add resistors in series, the resistance increases according to the equation: R = R₁ + R₂.

Parallel Resistance Addition

When you add resistors in parallel, the resistance of the circuit decreases.

Variable Resistor

A resistor whose resistance can be changed by moving a slider or turning a dial, e.g. dimmer switch.

Thermistor

A type of resistor that changes resistance depending on temperature; higher temperature results in lower resistance.

LDR (Light Dependent Resistor)

A resistor that changes resistance depending on the light; brighter light results in lower resistance.

Fixed Resistor

A resistor that has a constant resistance and is used to lower the current.

Diode

An electrical component that allows current to flow in one direction only.

Filament Lamp

A type of lamp that produces light by heating a filament until it glows.

Current-Voltage Relationship

The relationship between current and voltage for different components, which can be investigated by swapping components in a circuit.

Constant Resistance

A condition where the resistance remains the same regardless of the voltage applied.

Very High Resistance

A condition where there is no current until a specific voltage is reached.