AC Capacitors Flashcards
(11 cards)
What is Z?
Total Impedance
This is the total Resistance of a capacitor Ztotal is total impedance
Z = √(R²+²X)
Ztotal = √R² + (XL - XC)²
Z would be one path of the circuit’s reactance added up while Ztotal would be the entire circuit
What is Xc?
Capacitive Reactance
This is the resistance a capacitor gives to a circuit
Xc = 1/2πC*F
How does High frequency and low frequency affect reactance?
High frequence = Behaves almost like a regular wire, no reactance
Low frequency = Capacitor resists sudden charges
This is all due to electric fields. Not a lot of voltage is being held in the capacitor since this happens so fast, but the motion of electrons moving to and away from the dielectric which, due to the magnetic field, causes them to interact with eachother in a way that they’re both always moving either back or forth
In terms of capacitors with low and high capacitance, how do they both handle charges and voltage drops?
Small Capacitance = Charges quickly, voltage drops faster
Large cacitance = Charges slowly, voltage drops more slowly
Drops voltage, meaning discharge of energy
What is Irms vs Ipeak?
Irms - is the DC equivalent of the AC current
Vrms/Z
Ipeak - This is the highest point in the frequency that the current goes
Irms * √2
What is Vrms vs Vpeak?
Vrms - DC equivalent of AC voltage
Vrms = .7 * Vpeak or Irms * Z (Ohm’s Law)
Vpeak = 1.414 * Vrms
Convert mF to farads
.001
10 -3
m - mac - big mac has three buns
Convert uF to farads
10-6
.000001
Convert nF to farads
.000000001
10-9
n = nine = nine places
convert pF to farads
10-12
p = flip it and it’s a b
b = bakers dozen
bakers dozen = 13 but minus one letter “p” and it’s 12
What is ESR?
This is the actual resistance of the capacitor that’s not reliant on the frequency.
In real world electronics we use it in out Z equation:
Z = √(Resr)²+Xc²)
