54
2.11 Bicycle light
Circuit 29:
Simple bicycle light
Setup information
Install the transistor and the two diodes as shown in
Fig. 2.29.
Then install the three resistors and the
electrolytic capacitor. The seven jumper wires come next. The the jumper acting as switch (shown dashed)
is installed last. Only one end of the jumper wire is connected, the other is open. Check the placement on
the board again and only then connect the battery.
Components required:
1 x 2N3904 transistor,
1 x yellow LED,
1 x 1N4148 silicon diode,
1 x 470
Ω
resistor,
1 x 1 k
Ω
resistor,
1 x 10 k
Ω
resistor,
1 x 100 μF elec-
trolytic capacitor,
1 x breadboard, 1 x 9V
battery with clip con-
nector
Fig. 2.29:
Simple bicycle light
Experiment
Even if everything is wired correctly, nothing will happen at first; the yellow LED remains dark. When the
switch is closed, the LED light turns on. But when you open the switch, the LED will not turn off immediately
but will continue to glow for a while. At this point it is important that the light emitting diode is switched
via the transistor and the actual switch only needs to master the tiny control current of this transistor.
This will eliminate corrosion on the switching parts caused by switch sparks. If you are indeed using the cir-
cuit as bicycle light, you should use a super bright white LED and there ought to be a hub dynamo installed.
Traffic regulations must be observed.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.29.
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...
