93
2.28 Turn signal gentle to the eye
Circuit 68:
LED blinker 1 Hz
Setup information
Install the two transistors, the diode and the five resistors as shown in
Fig. 2.68
. Then install the three
electrolytic capacitors. The 13 jumper wires are next. Check the placement on the board again and only then
connect the battery.
Components required:
2 x 2N3904 transistors,
1 x red LED, 1 x 220
Ω
resistor, 2 x 10 k
Ω
resis-
tors, 2 x 22 k
Ω
resistors,
1 x 10 μF electrolytic capac-
itor, 2 x 100 μF electrolytic
capacitors, 1 x breadboard,
1 x 9V battery with clip
connector
Fig. 2.68:
LED blinker 1 Hz
Experiment
Even though, everything is wired correctly and the battery is installed, it may take some time until some-
thing happens. The circuit produces sine waves at a frequency of about 1 Hz. It will take a while until it
comes to live. But then it works reliably and tirelessly. The red LED flashes at regular intervals, gentle on the
eyes. The LED is not turned on or off abruptly, but increases and decreases its brightness steadily towards
the respective turning point. This is great for the eyes.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.68.
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...
