119
Circuit 94:
Slow LED flash
Setup information
Install the two transistors, the LED, the three resistors and the three electrolytic capacitors as shown in
Fig. 2.94.
The ten jumper wires come next. Check the placement on the board again and only then connect
the battery.
Components required:
1 x 2N3904 transistor,
1 x 2N3906 transistor,
1 x red LED, 1 x 100
Ω
resistor, 1 x 100 k
Ω
resistor, 1 x 220 k
Ω
resis-
tor, 1 x 1 μF electrolytic
capacitor, 2 x 10 μF
electrolytic capacitors,
1 x breadboard, 1 x 9V
battery with clip con-
nector
Fig. 2.94:
Slow LED flash
Experiment
If everything is wired correctly, the circuit immediately starts generating very short LED flashes at an interval
of about three seconds. The repetition frequency in our circuit is basically defined by C2, C3. Circuitries of
this kind can be used as a stroboscope in many applications.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.94.
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...
