Keywords and formulas Flashcards
(wheatstone bridge) what does R1/R2 equal to?
R3/R4
What does R1 equal to in the delta to wye transformation
(RaxRb)/(Ra+Rb+Rc)
What does R2 equal to in the delta to wye transformation
(RaxRc)/(Ra+Rb+Rc)
What does R3 equal to in the delta to wye transformation
(Ra+Rb)/(Ra+Rb+Rc)
What is an essential node?
A node where 3 or more elements join
What is a node?
A point where two or more circuit elements join
What is a path?
A trace of adjoining elements where no elements included more than once
What is a branch?
A path which connects two essential nodes.
What is an essential branch?
A path which connects two essential nodes without passing through any other essential nodes.
What is a loop?
A path whose last node is the same as the starting node
What is a mesh?
A loop that does not enclose any other loops
What is a Planar circuit?
A circuit that can be laid out on a plane iwht no crossing branches
What does Rth equal?
(Voc)/(Isc)
What load of resistance will give rise to maximum power transfer into the load?
The same amount of resistance as Rth
Does a Thevenin equivalent circuit include a resistor in parallel or in series?
In series
Does a Norton equivalent circuit include a resistor in parallel or in series?
In parallel
What are capacitors?
- Capacitors store energy in the form of electric charge
- Capacitors oppose the change in voltage across their terminals
- Change in voltage across the plates causes current to flow through the capacitor.
What is the formula for the voltage across a capacitor when discharging
Vc=Voexp(-t/RC)
What is the formula for voltage across a capacitor when charging
Vc=Vf[1-ecp(-t/RC)]
What are inductors
- An inductor stores energy in the form of a magnetic field surrounding its coil
- Inductors oppose the change in current through their terminals (or coil)
- Change in current causes voltage to be developed across the inductor terminals (due to magnetic flux)
whats the time constant of a Resistor-Inductor circuit
L/R
Is a diode a semiconductor
yes
what are diodes commonly used for?
rectification- turning AC into DC
What do diodes do to current?
they only allow current to flow in one direction
What is the forward voltage drop of silocon
0.7v
What is the forward voltage drop of Germanium
0.3v
What is the forward voltage drop of Gallium Arsenide
1.8v
What do zener diodes do
breakdown safely under reverse bias conditions
What is breakdown voltage also known as
Zener voltage
What do you do to semi conductors to turn them into p-type and n-type materials
dope them
How are diodes made
the fusion of a PN junction
what type of IV curves do diodes have
non linear
What does a sinusoid signal v(t) equal to
Vmsin(wt+%)
What is the phasor transform formula?
v(t)=Re(Vexpjwt)
What are the phasor relationships for capacitors and inductors
current leads voltage by 90 degrees (capacitors)
inductors- voltage leads current by 90
Z?
V/I
resistance?
/z/cos%
Y?
1/z
Conductance?
/Y/cos%
suceptance?
/Y/sin%
Why are bipolar junction transistors usefull?
small curents can be used to controll much larger ones
what are the 2 different types of transistor?
PNP NPN
What are the 3 terminal devices
collector
base
emitter
What are the characteristics of an ideal voltage amplifier
Av=infinity Ri=infinity Ro=0 They are differential amplifiers
Application of negative feedback
Negative feedback is commonly used in op amp circuits to reduce the gain and improve the properties of the amplifier.
What is the repercussion of the gain being assumed to be fininte? (non inverting amplifier)
V-=V+=Vi
equation of vi in a non inverting amplifier?
Vo x (R2)/(R1+R2)
What is the result of assumed infinte gain on a inverting amplifier?
V-=V+=0
What is V- called in a inverting amplifier?
Virtual earth
Formula for G? (non inverting)
[Vo/Vi]=[R1+R2/R2]
Formula for G? (Inverting)
[Vo/Vi]=-(R1/R2)
What does an inverting Summing amplifier do?
it is used to add up0 a number of voltages as in superposition
formula for Vo in a inverting summing amplifer?
Vo=-V1(R1/R2)-V2(R1/R3)
What does a differential amplifier do?
A differential amplifier can be used to amplify the differences between two voltages
What is the formula for Vo for a differential amplifer?
Vo=(V1+V2)R1/R2
What are the benefits of negative feedback on Op Amps
Negative feedback reduces gain
get more consistency
easy analysis
