Objective:
– Use a function generator and an oscilloscope to demonstrate that for two magnetically linked coils, the induced EMF is the differential of the supplied EMF in both sine and square waveforms.
Apparatus:
- 2 Gilley Coils
- Iron core, Copper core, Aluminum core
- Digital Oscilloscope (Tektronix TDS 2012C)
- Function Generator (BK Precision 4011A)
- 470 ohm limiting resistor (#2 resistor on the old EM1 resistor board)
- Leads
Method:
- Sine waveform: First input a sine wave, and notice that the output is also a sine wave but phase shifted by 90 degrees.
- Square waveform: Ask the students to predict what will happen when a square wave is inputted, then change the input to a square wave and notice the sharp spikes on the output corresponding to the upward and downward edges of the square wave. This demonstration may also be used to demonstrate the flux linkage between the two coils by substituting the iron core for air, copper and aluminum.
Settings:
Oscilloscope:
-
- Channel 1 = 5.0 volts (Settings may be varied; it depends on if the output level knob on the function generator is turned all the way down or not.)
- Channel 2 = 50.0 millivolts Main Horizontal Scale= 1.0 ms/div
- Noise level can be minimized on channel 2 by turning on the BW Limit function.
Function generator:
-
- set at 400 hertz