electrical circuits . ࣪⋆ ਏਓ Flashcards
what can a variable resistor do
can be adjusted in order to give a range of voltages
How do you calculate resistance
Voltage divded by current
what does the filament lamp follow
The filament lamp does not follow Ohm’s Law. Its resistance increases as the temperature of its filament increases
what are diodes
Diodes are electronic components that can be used to regulate the voltage in circuits and to make logic gates
describe the graph of a Diode
The diode has a very high resistance in one direction. This means that current can only flow in the other direction.
Describe the resistors connected in a series circuit
When resistors are connected in series, the current through each resistor is the same. In other words, the current is the same at all points in a series circuit.
What increases the total resistance in a series circuit
Adding components in series increases the total resistance in a circuit.
Hkw do you calculate power
Power = energy divided by time
What is Power measured in
Watts (W)
What is energy measured in
Joules (J)
What is time measured in
Seconds (s)
What are thermistors
Thermistors are used as temperature sensors, for example, in fire alarms. Their resistance decreases as the temperature increases.
What are LDRs
The LDR
LDRs (light-dependent resistors) are used to detect light levels, eg in automatic security lights. Their resistance decreases as the light intensity increases.
What does LDR stand for
light dependant resistor
What are resistors used for
Used to control or fix the current
