Maker Factory ELECTRONICS EXPERIMENTS BOX Manual page 41

Circuit 18: Boring double turn signals
Setup information
Install the two transistors as shown in Fig. 2.18. Install the two LEDs. Now it is time for the six resistors.
Finally insert the eight jumpers. Check the placement on the board again and only then connect the battery.
Experiment
If everything is wired correctly, the two LEDs will start flashing alternately after a certain run-up time. The
flashing frequency is at 2.5 Hz. This is basically the same circuit we used in the previous experiment. The
only difference is the value of the resistors; the ones charging the electrolytic capacitors are bigger.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.18.
Components required:
2 x 2N3904 transistors,
1 x red LED, 1 x green LED,
2 x 1 kΩ resistors,
2 x 100 kΩ resistors,
2 x 220 kΩ resistors,
2 x 10 μF electrolytic
capacitors, 1 x breadboard,
1 x 9V battery with clip
connector
Fig. 2.18: Boring double turn
signals
43