42
2.6 Double turn signals
Circuit 17:
Awesome double turn signals
Setup information
Install the two transistors as shown in
Fig. 2.17.
Install the two light-emitting diodes. Now it is time for the
six resistors. Finally insert the eight jumpers. Check the placement on the board again and only then con-
nect the battery.
Components required:
2 x 2N3904 transistor,
1 x red LED, 1 x green LED,
2 x 1 k
Ω
resistors,
2 x 22 k
Ω
resistors,
2 x 100 k
Ω
resistors,
2 x 10 μF electrolytic capac-
itors, 1 x breadboard, 1 x 9V
battery with clip connector
Fig. 2.17:
Awesome double turn
signals
Experiment
If everything is wired correctly, the two LEDs will start flashing alternately. The flashing frequency is at 2 Hz.
Try out other values for the electrolytic capacitors C1 and C2 and the resistors R2 to R5. At times one LED
will glow longer than the other, usually the flashing frequency will be different; and at times the circuit will
not work at all. Then no LED will go on, or one will be steady lit or the other will not turn on at all.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.17.
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...
