Resistance = a measure of the opposition to current flow in an electrical circuit - Electrical components like bulbs resist the flow of current.
Resistance is measured in ohms (Ω).
Equation:
resistance (R) = voltage (V) / current (I)
The greater the resistance, the less current flows through it.
variable resistor can change their resistance - allows a range of readings to be collected.
FILAMENT LAMP
As voltage increases, the current increasing at a decreasing rate.
FILAMENT LAMP
The resistance of lamp increases, voltage increases as the perspire of lamp increases causing larger vibrations = more collisions between free ions and electron.
FILAMENT LAMP
WIRE AT CONSTANTTEMPERATURE
WIRE AT CONSTANT TEMPERATURE
Resistance of a wire at a constant temperature is constant- calculating resistance with any pair of voltage and current will give the same value.
(Silicon) DIODE
As voltage increases, current increases after (approximately) 0.4V - 0.7V, at an increasing rate.
DIODE
Only works in one direction and has a forward voltage where it starts.
(Silicon) DIODE
If a lot of resistors are ina. circuit and no safety resistor, ammeter may be damaged as resistance would be too low (zero resistance) and producing very high current so ammeter could be overloaded.
