205
Circuit 180:
HF generator 420 kHz
Setup information
Install the transistor, the four resistors, the four ceramic capacitors and the fixed value inductor as shown
in
Fig. 2.180
followed by the eight jumpers. Check the placement on the board again and only then connect
the battery.
Components required:
1 x 2N3904 transistor,
2 x 10 k
Ω
resistors,
2 x 22 k
Ω
resistors,
3 x 1 nF ceramic capaci-
tors, 1 x 100 nF ceramic
capacitor, 1 x 220
μH fixed inductance,
1 x breadboard, 1 x 9V
battery with clip con-
nector
Fig. 2.180:
HF generator
420 kHz
Experiment
This circuit generates HF radio waves at a frequency of about 420 kHz. A portable MW radio makes the first
harmonic of this radiation audible at 840 kHz. This is a standard circuit in analogue receiver technology and
known as Colpitts oscillator.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.180.
Summary of Contents for ELECTRONICS EXPERIMENTS BOX
Page 4: ......
Page 265: ...267 Fig 3 56 Cir cuit 56 Audio limiter Fig 3 57 Circuit 57 Amplifier for a storm detector...
Page 269: ...271 Fig 3 64 Circuit 64 Stabilizer for 1 9 V Fig 3 65 Circuit 65 Stabilizer for 2 5 V...
Page 275: ...277 Fig 3 80 Circuit 80 Quiztimer 30 seconds Fig 3 81 Circuit 81 Handy diode tester...
Page 315: ...317 Fig 3 179 Circuit 179 HF generator 150 kHz Fig 3 180 Circuit 180 HF generator 420 kHz...
