Category Archives: AC Circuits

Visual AC

Demo: EM-L-VA
Pira Index: 5L 30.21

 Lab Equipment  Directions
  1.  Neon lamp on a cord
  1.  Swing the cord around in a circle and see that the light is actually not constant, there are light and dark bands.
  2. Observe the light standing still. Persistence of vision leads you to believe that the light is constantly lit.

 

RLC Circuit Model

Demo: EM-L-RL
Pira Index: 5L 20.10

 Lab Equipment  Directions
  1.  Foamboard superimposed waves
  1.  With the two waves folded together, let one color represent current, the other color represent voltage.
  2. Slide waves to show in phase relationship between the two in a resistive circuit.
  3. Slide current ahead of voltage to represent the phase shift of a capacitive circuit.
  4. Slide voltage ahead of current to represent the phase shift of an inductive circuit.

 

RC Circuit Box

Demo: EM-L-RC
Pira Index: 5L 20.00

 Lab Equipment  Directions
  1.  Oscilloscope (Philips)
  2. RLC box
  3. Function generator (Pasco 9598)
  4. BNC-m to AA lead
  5. 2 BB leads
  6. 2 probe adapters
  7. 2 spade adapters
  1.  Connect the equipment as shown.
  2. Set the function generator on square wave, multiplier at 10, and frequency knob at 10 (100Hz). Turn the amplitude up about half way.
  3. Set the RLC box switch to RC.
  4. Set the scope as follows (settings will show on the LCD panel): toggle A switch to 2V, toggle MTB switch to 2 mS
  5. The repetitive charge and discharge of the capacitor will show up on the trace as shown below (curving wavefront is charging, sudden straight drop is the discharge).

 

 

New AC Circuits

Demo: EM-L-NA
Pira Index: 5L 20.13

 Lab Equipment  Directions
  1.  RLC box
  2. 2 Fluke 8000A DMM
  3. HP 204C oscillator
  4. 3 Probe-B leads
  5. 1 BB leads
  6. 2 BS leads
  7. Power strip
  1.  Connect the apparatus as shown.
  2. Set the DMM’s at AC 20v setting.
  3. Adjust the frequency of the oscillator until the voltage readings equalize. At this point the inductor and capacitor are in resonance.

 

 

Driven RLC Resonance Circuit

Demo: EM-L-DR
Pira Index: 5L 20.18

 Lab Equipment  Directions
  1.  Oscilloscope (Philips)
  2. RLC box (clear box)
  3. Function generator (Pasco 9598)
  4. 2 DMM (Fluke 87)
  5. 2 BNC-m to BB-f adapters
  6. 4 Probe-B leads
  7. 2 spade adapters
  8. 4 banana/banana leads
  9. 1 probe adapter
  1.  Connect the equipment as shown.
  2. Set RLC box switch at middle position.
  3. Connect both DMMs for voltage and set on V AC.
  4. Set function generator amplitude low, sine wave, and frequency at ~80 Hz. Adjust amplitude until the connected Fluke meter reads 4.5 volts.
  5. Set the scope as follows: toggle A switch to 2V, toggle B switch to 1V, toggle MTB to 2 mS, push A/B button to AB.
  6. Check voltage across R, then L, then C.

 

 

RLC Damped Oscillating Circuit

Demo: EM-L-DO
Pira Index: 5L 20.00

 Lab Equipment  Directions
  1.  Oscilloscope (T 912)
  2. RLC box
  3. Function generator (Pasco 9598)
  4. Ceramic potentiometer-8 ohm
  5. BNC to AA lead
  6. 2 BA leads
  7. 2 probe adaptors
  8. 2 BS leads
  1.  Connect the equipment as shown. Put the RLC box switch on RLC.
  2. Adjust the function generator to a square wave with maximum frequency of 6.5 Hz.
  3. Set the oscilloscope as follows: Int. Trigger, Single Sweep, Channel #1 at 20mv and 10-50ms
  4. Push the “store” button. When you push the mode to “single sweep” you should see the dampening effect through the resistor as the capacitor and inductor interact.

 

 

AC Circuit with New Scope

Demo: EM-L-AC
Pira Index: 5L 20.13

 Lab Equipment  Directions
  1.  Oscilloscope (Tektronix TDS 3014B)
  2. FLC box (clear)
  3. Function generator (Pasco PI 9587C)
  4. 2 multimeters (Fluke 75 III)
  5. 3 probe adaptors
  6. 2 DB-f to BNC-m adaptors
  7. 1 DB-BNC lead
  8. 2 spade adaptors
  9. 8 BB leads (stackable)
  10. Floppy disk with configuration backup
  11. Power strip
  1.  Set the function generator to approx. half amplitude and frequency adjust to approx. 70Hz. The RLC box switch should be in the center.
  2. Turn on the scope (lower left). Put disk in drive.
  3. Press “save/recall” then “save setup”, then “setup 1 EM–L-AC”
  4. Two waves should be seen on the scope. The tall blue wave is the reference voltage; the short wave is the combined VL and VC. Turn switch on RLC box to side position watching the shifting short wave. RL it leads, RC it lags the reference.
  5. W/DMM’s on AC voltage adjust frequency of until readings equalize. At this point the inductor and capacitor are in resonance.