239
Circuit 214:
Detector receiver with amplifier
Setup information
Install the transistor, the diode, the two resistors, the fixed value inductor and the two ceramic capacitors as
shown in
Fig. 2.214.
The nine jumper wires come next. Last but not least connect the Piezo element. Check
the placement on the board again and only then connect the battery.
You can significantly increase the sensitivity of the Piezo element by using a sound plate or even a sound
box. Read more about it in Chap. 1.2.3
Components required:
1 x 2N3904 transistor,
1 x BAT85 Schottky
diode, 1 x 2.2 k
Ω
resis-
tor, 1 x 220 k
Ω
resis-
tor, 1 x 1 nF ceramic
capacitor, 1 x external
ceramic capacitor (see
Experiment for value),
1 x 1 μF electrolytic
capacitor, 1 x 10 μF
electrolytic capacitor,
1 x 220 μH fixed induct-
ance, 1 x Piezo element,
1 x breadboard, 1 x 9V
battery with clip con-
nector
Fig. 2.214:
Detector receiver
with amplifier
Experiment
A detector receiver is the bedrock in radio technology. Use a long, freely suspended wire as antenna. A
ground connection as short as possible is made to a water line. For the capacitor in parallel to the fixed
inductance, you could preferably use a small 200 pF wire capacitor. Alternatively, experiment with all sorts
of parallel and series combinations using 10 pF, 100 pF or 220 pF ceramic capacitors. One of these combi-
nations should offer favourable conditions for a clear reception of the nearest local broadcaster on MW. At
night you should be able to receive several other strong stations. You will find that volume and selectivity
have significantly increased in our circuit compared to the previous version.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.214.
Содержание ELECTRONICS EXPERIMENTS BOX
Страница 4: ......
Страница 251: ...253 Fig 3 27 Circuit 27 4 seconds switch off delay Fig 3 28 Circuit 28 20 seconds switch off delay...
Страница 258: ...260 Fig 3 42 Circuit 42 Active 8 5V battery monitor Fig 3 43 Circuit 43 Active 7 8V battery monitor...
Страница 260: ...262 Fig 3 46 Circuit 46 Meters for 1 5 V Zener diodes and higher Fig 3 47 Circuit 47 Discreet 2 2V Zener diode...
Страница 261: ...263 Fig 3 48 Circuit 48 Discreet 2 9V Zener diode Fig 3 49 Circuit 49 Discreet 3 7V Zener diode...
Страница 265: ...267 Fig 3 56 Cir cuit 56 Audio limiter Fig 3 57 Circuit 57 Amplifier for a storm detector...
Страница 269: ...271 Fig 3 64 Circuit 64 Stabilizer for 1 9 V Fig 3 65 Circuit 65 Stabilizer for 2 5 V...
Страница 275: ...277 Fig 3 80 Circuit 80 Quiztimer 30 seconds Fig 3 81 Circuit 81 Handy diode tester...
Страница 290: ...292 Fig 3 118 Circuit 118 HF watch dog with LED indicator Fig 3 119 Circuit 119 HF watchdog with moving coil instrument...
Страница 295: ...297 Fig 3 130 Circuit 130 4 seconds switch on delay Fig 3 131 Circuit 131 15 seconds switch off delay...
Страница 298: ...300 Fig 3 136 Circuit 136 NAND gate with moving coil instrument Fig 3 137 Circuit 137 Input level Mixing console...
Страница 300: ...302 Fig 3 140 Circuit 140 Electrometer with moving coil instrument Fig 3 141 Circuit 141 Simple AM Radio...
Страница 315: ...317 Fig 3 179 Circuit 179 HF generator 150 kHz Fig 3 180 Circuit 180 HF generator 420 kHz...
Страница 324: ...326 Fig 3 202 Circuit 202 3 seconds switch on delay Fig 3 203 Circuit 203 7 seconds switch on delay...
Страница 325: ...327 Fig 3 204 Circuit 204 Piercing siren sound with Piezo element Fig 3 205 Circuit 205 Discrete Operational ampli fier...
Страница 328: ...330 Fig 3 210 Circuit 210 Discreet 5 2V Zener diode Fig 3 211 Circuit 211 Discreet 7 4V Zener diode...
