Electricity Flashcards
What happens to the electrons in two insulators when they are rubbed together?
They both exchange electrons and gain opposite charges. They both have equal amounts of charge.
What is the symbol for a variable resistor?
opaque rectangle with a diagonal line through it, no tail
What is the symbol for a thermistor?
opaque rectangle with a diagonal through it, slight tail on bottom of line
Where must an ammeter be in a circuit relative to the component?
In series.
How do you calculate current?
I = Q ÷ t
I is the current in amperes (amps), A
Q is the charge in coulombs, C
t is the time in seconds, s
Where must a voltmeter be in relation to a component?
In parallel.
How do you calculate potential difference(voltage)?
V = W ÷ Q
V is the potential difference in volts, V
W is the work done (energy transferred) in joules, J
Q is the charge in coulombs, C
How do you calculate resistance?
V = I × R !!!!REVERSED!!!
V is the potential difference in volts, V
I is the current in amperes (amps), A
R is the resistance in ohms, Ω
The equation can be rearranged to find the resistance: R = V ÷ I
CORRECT : R = V ÷ I
What shape does a resistor produce on a current potential difference graph?
perfectly proportional positive correlation
What shape does a filament bulb produce on a current potential difference graph?
stretched s positive correlation (ITS THE CURVED ONE LOL)
What shape does a diode produce on a current potential difference graph?
horizontally stretched J shape
How do thermistors work?
- At low temperatures, the resistance of a thermistor is high and little current can flow through them
- At high temperatures, the resistance of a thermistor is low and more current can flow through them
How does a light-dependent resistor work?
In the dark and at low light levels, the resistance of an LDR is high and little current can flow through it
In bright light, the resistance of an LDR is low and more current can flow through it
What does alternating current(AC) look like? ~
A clear waveform fluctuating between high and low. (SQUIGGLY LINE: ~~~~~~~~~) :D
What does direct current look like?
Straight line:
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