113
2.37 Constant current sources for LEDs
Circuit 88:
constant current with FET transistor
Setup information
Install the FET transistor and the three diodes as shown in
Fig. 2.88.
The three jumper wires are next.
Check the placement on the board again and only then connect the battery.
Components required:
1 x J111 FET transistor,
1 x red LED, 1 x green
LED, 1 x yellow LED,
1 x breadboard, 1 x 9V bat-
tery with clip connector
Fig. 2.88:
constant current with
FET transistor
Experiment
If everything is wired correctly, current will always be high enough for the LEDs to shine bright – even if the
battery voltage has dropped.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.88.
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...
