Thermal Overcurrent Circuit Breaker 3120-F 176 ☎ 10 3120 rocker switch/circuit breaker
The tuned circuit - kau tuned circuit.pdf · The Tuned Circuit Aim of the experiment Display of a...
Transcript of The tuned circuit - kau tuned circuit.pdf · The Tuned Circuit Aim of the experiment Display of a...
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The Tuned Circuit
Aim of the experiment Display of a decaying oscillation. Dependence of L, C and R.
Circuit
Equipment and components 1 Rastered socket panel
1 Resistor R1 = 10 Ω, 1 Resistor R2 = 1 kΩ
2 Capacitors C1, C2 = 0.1 µF
1 Capacitor Ck = 4.7 nF
1 Capacitor Cp = 10 nF
1 Coil, 500 turns, 1 Transformer core
1 Function generator
1 Oscilloscope
2 Sets of probes
Bridging plugs, Connecting leads
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Conducting the experiment
Part 1 1. Assemble the measuring circuit.
2. Function generator: f = 100 Hz (square - wave)
U1 approx. 5 Vpp
Apply this signal to the differentiator (R2 C1).
At the output spike pulses will appear with positive leading and negative trailing
edges, which excite the tuned circuit.
Oscilloscope: Y1 (5 V/cm) first connected to the square-wave signal and then to the
spike signal.
Y2 (100 mV/cm) connected to the tuning circuit.
Time base: 1 ms/cm; AT
Coil without iron core. Short-circuit R1 = 10 Ω.
3. You should get the following graph. Make a true-to-scale drawing.
Part 2 4. Adjustments as in part 1, but slowly insert the core into the coil. Observe the
frequency
€
1T⎛
⎝ ⎜ ⎞
⎠ ⎟ of the decaying oscillation.
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Part 3 5. Adjustments as in part 2, but connect a capacitor Cp = 10 nF in parallel to C2.
Part 4 6. Adjustments as in part 3, but remove the core, and also remove the short-
circuit across the resistor R1 = 10 Ω. When doing so, observe the decaying oscillation.
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Parallel Resonant Circuit
Aim of the experiment Measuring the resonance frequency and displaying the resonance curve.
Changing the resonance frequency
Measuring the phase of the inductive and capacitive reactive current with respect to the resonance voltage
Measuring bandwidth and Q
Circuit
Equipment and components 1 Rastered socket panel
1 Resistor R1 = 10 Ω
1 Capacitor C = 0.1 µF
1 Capacitor Ck = 4.7 nF
1 Capacitor Cp = 10 nF
1 Coil, 500 turns, 1 Transformer core
1 Function generator, 1 Oscilloscope
2 Sets of probes
Bridging plugs, Connecting leads
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Conducting the experiment
Part 1
1. Set U1 = 2 Vpp (sine). Measuring point A (Y1 :
€
1 Vcm
).
2. Assemble the circuit without the resistor R = 10 Ω (short circuit), and without
inserting the iron core into the coil.
3. Connect Y2 (
€
1 Vcm
, 10:1) to the point of Ck, L, C = measuring point B (‘hot’
point of the circuit).
4. Change the frequency until a voltage maximum is observed at Y2. Read off the
frequency.(This is the resonant frequency fres of the parallel-tuned circuit).
fres =
Ures =
Part 2.A
Measuring the resonant curve.
5. Connect Y1 (
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200mVcm
) to measuring point B.
Set U1 to Ures = 1.2 Vpp (6 divisions.).
6. Measure the output for frequencies above and below the resonance frequency.
7. Tabulate the results and draw a graph.
In order to characterize a tuned circuit, those frequencies above and below the
resonance frequency are important where the voltage has dropped to:
€
Ures
2 = 0.707 Ures.
f/ kHz
U2/ Vpp
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Part 2.B 8. Repeat the measurement with R = 10 Ω connected in series to the coil.
f/ kHz
U2/ Vpp
Make a diagram of both curves with U2 = Function of frequency F (f)
Exercise • Measure the band width (b), where b = 2 Δf
b =
• Measure the quality factor Q which is defined as the ratio between:
€
resonance frequencyband width
=f res2Δf
=Q
Q =
Part 3
9. Adjust the frequency of the generator to f = 5 kHz (2 Vpp).
10. Connect Y2 (
€
0.5 Vcm
, 10 : 1) to measuring point B and trigger on Y2.
11. Remove Y1. Slowly insert the iron core and see if a maximum can be
obtained:
Ures =
Part 4
12. Connect the capacitor Cp = 10 nF in parallel to the capacitor C = 0.1 µF and
retune the frequency for maximum:
fres =
Ures =
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Series Resonant Circuit
Aim of the experiment Measure the course of the voltages across the resistor, the coil and the capacitor as a
function of the frequency
Measure bandwidth, and quality factor
Circuit
Equipment and components 1 Rastered socket panel
1 Resistor R = 10 Ω
1 Capacitor C = 0.1 µF
1 Coil, 500 turns, 1 Transformer core
1 Function generator, 1 Oscilloscope
2 Sets of probes
Bridging plugs, Connecting leads
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Conducting the experiment • Measure the voltages across the resistor: UR.
• Measure the voltages across the capacitor: UC.
• Measure the voltages across the coil: UL.
With U1 = 2 Vpp
€
fkHz
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UR
mVpp
€
UL
Vpp
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UC
Vpp
Make a diagram of UR, UL and UC .
Exercises
• Calculate the band width b :
€
b = 2Δf =
• Calculate the quality factor Q :
€
Q =fres2Δf
=