Series Circuits
Current is the same on each resistor
Resistance RT=R1+R2+R3+Rn
Current IT= V/RT
Voltage VT= V1+V2+V3+Vn(KVL)
Voltage Drop VR=(IT)(R)
Voltage Divider Vx=(Rx/RT)VT
Power Total =(VS)(I) or (I2)(RT) or VS2/RT
Power in a resistor = (Vx)(Ix)
Power is measured in WATTS (W)
Convert Voltage Source to Current Source
IS=VS/RS
Terminal Equivalency ILOAD=VS/(RS+RL)
Thevenin Equivalent
VTH use voltage divider rule
RTH use total resistance
Color Code 6=Blue
4 bands=
0=Black
7=Violet
1=Brown
8=Gray
2=Red
9=White
5 band=
3=Orange
+/-5%=gold
4=Yellow
+/-10%=silver
5=Green
Ohms Law
I=V/R
V=(I)(R)
Parallel Circuits
Voltage is the same across all resistors
1
Resistance R T =
1/R 1 + 1/R 2 + 1/R 3 + 1/R n
RT for 2 resistors=(R1)(R2)/(R1+R2)
Current IT= I1+I2+I3+In(KCL)
Current Divider I1=((R2)/(R1+R2))IT
For 3 or more R’s Ix=(RT/RX)IT
Power Total= (V)(IT) or (IT2)(RT) or V2/RT
Convert Current Source to Voltage Source
VS=(IS)(RS)
1&2 are values
3 is the multiplier
4 is tolerance
1,2,&3 are values
4 is the multiplier
5 is the tolerance
R=V/I
CHARGE(Q)= #of electrons/6.25x 1018electrons/C
V=W/Q
I=Q/t
P=W/t
W=(P)(t)
Capacitors
Total Series Capacitance Ct=1/((1/C1)+(1/C2)….)
Capacitor Voltage Vx=(Ct/Cx)Vt
Total Parallel Cap Ct=C1+C2+C3….
Time constant τ=RC
Time Constant %ages
1= 63%
2= 86%
3= 95%
4= 98%
5= 100%
Pico (p) -12
Milli (m) -3
Giga (G) 9
nano (n) -9
Kilo (k) 3
Tera (T) 12
micro (µ) -6
Mega (M) 6
Efficiency = Pout/Pin
Pout= Pin-Ploss
Sine wave
f= 1/T
T=1/f
Vpp= 2Vp peak to peak
Ipp= 2Ip
Vrms= (0.707)(Vp)
Irms= (0.707)(Ip)
Degrees to Rad= (πrad/180)xdegrees
Rad to Degrees= (180/πrad)xRad
Sine wave Instantaneous value at 90 ref point=
v=Vpsinθ
percent duty cycle= (tw/T)100%
Total Impediance Z= R 2 + X 2
θ= -tan-1(Xc/R)
Xc= 1/ 2πfC
Xc= Vc/I
Vc= Vs − Vr
I=Vr/R
CURRENT in a capacitor leads VOLTAGE ICE
CURRENT is in phase with VOLTAGE in resistors