206
2.84 Simple battery monitor
Circuit 181:
Simple 7.5V battery monitor
Setup information
Install the two transistors, the diode and the four resistors as shown in
Fig. 2.181
followed by the ten
jumper wires. 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 2.2 k
Ω
resistor, 2 x 10 k
Ω
resis-
tors, 1 x 22 k
Ω
resistor,
1 x breadboard, 1 x 9V bat-
tery with clip connector
Fig. 2.181:
Simple 7.5V battery
monitor
Experiment
The circuit is used to monitor battery voltage. If voltage is less than 7.5V, the red LED turns on. When the
battery breakdown voltage is finally reached, the LED turns off again.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.181.
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...
