Circuits Flashcards
What is the time constant?
The product of resistance and capacitance
What does the time constant describe?
The time taken for a capacitor to charge to 63%
What is the equation for the time constant?
T =RC (T=tau)
When is a capacitor said to be fully charged?
After 5 time constants
What happens when a capacitor becomes fully charged?
Capacitors block d.c. , no current flows
When fully charged, do capacitors allow a.c. Or d.c. To flow?
A.c.
How does a capacitor charge?
Capacitors let charge more onto it as it charges and more off it as it discharges
What happens to the rate of charge and discharge on a capacitor as the frequency is increased?
Rate increases
What is the capacitive reactance?
The effective rate of flow of charge
What can be said about the ease of flow of charge on a capacitor?
The bigger the capacitor and higher the frequency the easier it is for charge to continually move in the circuit
What is reactance measured in?
Ohms
What is an inductor?
A substance that can store energy and react to different frequencies in an a.c. Circuit
What is inductance?
A coil of wire with negligible resistance that is used in the growth and decay of a magnetic field
What is self-inductance?
When the induced voltage does not require any external power supply
What is lenz’s law?
The induced emf in a coil always opposes the charge that causes it
