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32 Cards in this Set
 Front
 Back
voltage, V 
U/Q (energy per unit charge) 

Vs 
Vr + Vb 

Current, I [A] = 
delta Q/ delta t 

Current, I = 
n.A.Vave.e 

ohms law 
R = V/I 

Impedance, Z 
Z = V/I 

Capacitance, C 
= Q/V 

Reactance of capacitor, Xc 
= V(t)/C(t) = 1/jwc 

reactance of capacitor, Xc 
= 1/wc = 1/2pifC 

Voltage across inductor, VL 
= L . dI/dt 

impedance across inductor, ZL 
= XL = jwL 

Power, P 
= VI = I^2R = V^2/R 

rms value 
= A/SQRT2 

Irms 
= Imax/SQRT2 

Vrms 
= Vmax/SQRT2 

Prms 
= Vrms . Irms 

Energy 
= P x t 

Cost
kWh 
kWh x running time x £ per kWh


Voltage across potential divider 
V1 = R1/R1+R2 . Vs 

Current divider rule 
I1 = R1/R1+R2 . Is 

Linear circuit 
Vout = k Vin 

Low pass filter  gain 
G = Vout/Vin = Xc/R+Xc 

Low pass filter  gain 
G = 1 / SQRT(1 + (wCR)^2) 

Critical frequency, fc 
fc = 1 / 2.pi.RC 

High pass filter  Vout, 
Vout = R / R+Xc . Vin 

High pass filter, gain 
G = Vout/Vin  = wCR / SQRT( 1 + (wCR)^2 ) 

Time Constant, tau 
tau = RC 

98% for time constant 
= 4(tau) 

Diode equation 
Id = Is ( e^(qV/nkT) 1 ) Is  reverse saturation current k  boltzmann constant T  absolute temperature V  applied voltage across diode n  ideality factor ( n=1=ideal diode) q  charge of electron 

Kirchoffs Current rule (KCR) 
The total current entering a node in a circuit is equal to the total current leaving that node entering node +ve leaving node ve 

Kirchhoffs Voltage rule (KVR) 
The sum of all voltage sources and drops (sinks) around a closed circuit loop 

Inductance, L 
= N^2 . uo . ur A / l 