Do nowDo now: : The AC supply voltage shown is applied across a 1kThe AC supply voltage shown is applied across a 1kΩΩ resistor. resistor.

Friday, April 21, 2023

CalculateCalculate:: 1) The frequency of the AC supply1) The frequency of the AC supply

2) The peak current2) The peak current

3) 3) The maximum power outputThe maximum power output

SketchSketch:: 4) The graph of current vs time4) The graph of current vs time

5) Power vs time5) Power vs time

Friday, April 21, 2023

Homework:

Set 1 & 2 should be finished

Set 3 (inductors) due 18 Sep

Mid-unit Test:

Wednesday 18th September (P3)

Kirchoff and internal resistance

Capacitors & inductors

LO21:LO21: Define RMS voltage (current and power) Define RMS voltage (current and power) in terms of their peak valuesin terms of their peak values

Today’s Kaupapa:

The RMS value is usually quoted, not the peak value,and can be compared to the DC values (same power)

AC Voltage DC Voltage (with same power output)

Vrms

Vmax

2maxV

Vrms

2maxI

I rms

(See text pg 263-264 for derivations of these formulae)

ExampleExample::

The household power supply in NZ is 240V AC at 50Hz

a)Find the peak voltage of the household supply

b)Sketch a graph of voltage vs time for 1 cycle(with appropriate values and labels on the axes)

c) Find the peak and RMS value of the current in a 100W light bulb connected to the household supply

Do Activity 16ADo Activity 16A