1. Non-ideal Power Supply
Power supplies and batteries have an “internal resistance” or “output impedance” that limits the amount of current it can output.

2. Non-ideal Power Supply
Power supplies and batteries have an “internal resistance” or “output impedance” that limits the amount of current it can output.
Voltage “Droop”

3. Non-ideal Power Supply
Power output depends on load resistance RL qL RL
Max power occurs when
RL = RS
“Impedance matching”

4. Inductors
A coil of wire produces a magnetic field B(t), which can induce and electric field E(t) and voltage V(t).
Inductance of a Solenoid
μ = magnetic susceptibility
n = # turns per unit length
l = length
A = cross sectional area

5. Linear Variable Displacement Transducer (LVDT)
Inserting a steel rod into a solenoid changes its inductance.

6. Inductive Transducers
Reluctance tachometer - measures angular frequency ω or RPMs.
Road sensor – coil of wire in the road senses the presence of a car

7. Tesla Models S – All electric, 400 HP

8. AC Induction Motor – 1,000 Amps at 300 V
300,000 W = 400 HP
Instantaneous torque!
No transmission, no fuel pump, no water pump, no valves… Very few moving parts!

9. Alternating Current (AC)
Applied voltage oscillates sinusoidally
V = “peak amplitude”
Vpp = “peak-to-peak”
VRMS = “root-mean-square”

10. Alternating Current (AC)
The graph shown below is wrong…
why?

11. Complex Numbers Number line – 1 degree of freedom amplitude only
Complex plane – 2 degrees of freedom amplitude and phase
where

12. Complex Impedances R Resistor Capacitor C L Inductor

13. Complex Impedances In the end, we only consider imaginary part.
Complex impedances contain information about both amplitude and phase.
Ohm’s Law
In the end, we only consider imaginary part.