Topic 2a- Circuits Flashcards
Voltmeters are always connected ________ .
in parallel.
Ammeters are always connected _________ .
in series.
Voltmeters measure…
potential difference.
Ammeters measure…
current.
What is current?
The rate of flow of charge.
What is the equation for charge flow (in coulombs)?
Q=It Charge flow (C)= current (A) x time (s)
What is potential difference?
The driving force that pushes a charge round a complete circuit.
What is resistance?
Anything in the circuit which reduces the flow of current.
What is the equation for potential difference (that links to resistance and current)?
V=IR
potential difference(V)= current(A) x resistance(Ω)
At a constant temperature, the current flowing through an ohmic conductor is…
…directly proportional to the potential difference across it.
What is Ohm’s law?
The voltage across a conductor is directly proportional to the current flowing through it, provided all physical conditions, such as temperature, remain constant.
What are I-V graphs?
Graphs that show current-potential difference.
What does a curved line on an I-V graph mean?
That the component is non-linear.
What does a straight line on an I-V graph mean?
That the component is linear.
What relationship do diodes have with current?
Will only really let current flow one way through it, otherwise the resistance is very high.
Voltage _____________ across components in parallel.
Voltage remains the same across components in parallel.
Voltage _____ in series.
Voltage splits in series.
Current _____ in parallel.
Current splits in parallel.
Adding resistors in parallel…
…increases total current through a circuit and decreases resistance.
Adding resistors in series…
…increases the total resistance through the circuit.
The more light an LDR has…
…the lower the resistance.
The less light and LDR has…
…the higher the resistance.
LDR stands for-
Light dependent resistor.
The greater the temperature, the ________________ a thermistor has.
less resistance
The less the temperature, the ________________ a thermistor has.
greater resistance
