The Meissner oscillating circuit used in this experiment should
demonstrate the principle of deattenuation of an oscillating
circuit via feedback. A system consisting of an amplifier and a
feedback circuit can be caused to oscillate at a specific frequency
if amplification is at least large enough to compensate the loss in
amplitude in the feedback circuit and the feedback voltage at the
desired frequency is in-phase with the amplified voltage. This set
of requisites, known as Barkhausen's Precondition for Self-
Excitation, can be fulfilled by the circuit in this experiment. The
feedback factor, i.e. the ratio of the number of turns on the
oscillation coil to the number on the feedback coil, is 4:1.
Therefore, the voltage amplification of 4 is sufficient to
fulfill the precondition for the amplitude.
The precondition for phase is only fulfilled for the intrinsic
frequency of the oscillating circuit because there is a phase shift
between voltage and current for all other frequencies.
Generate an oscillating circuit of undamped electromagnetic
oscillation by feedback via a transistor amplifier stage.
| Materiallist (Excerpt) |
Product |
Amount |
|
Power supply 0...12 V DC/ 6 V, 12 V AC, 230 V
|
13505-93
|
1
|
|
U-core
|
07832-00
|
1
|
|
Potentiometer module 10 kOhm, SB
|
05625-10
|
1
|
|
Coil, 400 turns
|
07829-01
|
1
|
|
Coil, 1600 turns
|
07830-01
|
1
|
|
Earphones, 2kOhm,with 4mm-plugs
|
06811-00
|
1
|
|
Interrupted connector module, SB
|
05601-04
|
1
|
|
Yoke
|
07833-00
|
1
|
|
NPN transistor module BC337, SB
|
05656-00
|
1
|
|
Junction module, SB
|
05601-10
|
2
|
|
Straight connector module with socket, SB
|
05601-11
|
1
|
|
Angled connector module with socket, SB
|
05601-12
|
1
|
|
Resistor module 500 Ohm, SB
|
05613-50
|
1
|
|
Resistor module 47 kOhm, SB
|
05615-47
|
1
|
|
Capacitor module 47 nF, SB
|
05642-47
|
1
|
|
Capacitor module 47 µF non-polar electrolytic, SB
|
05645-47
|
1
|
|
Straight connector module, SB
|
05601-01
|
3
|
|
Angled connector module, SB
|
05601-02
|
2
|
|
T-shaped connector module, SB
|
05601-03
|
4
|
|
Connecting cord, 32 A, 500 mm, red
|
07361-01
|
2
|
|
Connecting cord, 32 A, 500 mm, blue
|
07361-04
|
2
|
|
Connecting cord, 32 A, 250 mm, red
|
07360-01
|
1
|
|
Connecting cord, 32 A, 250 mm, blue
|
07360-04
|
1
|
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