67
2.17 Active battery monitor
Circuit 42:
Active 8.5V battery monitor
Setup information
Install the two transistors, the two diodes and the eight resistors as shown in Fig. 2.42. Then install the two
electrolytic capacitors. The fourteen jumper wires come next. Check the placement on the board again and
only then connect the battery.
Components required:
1 x 2N3906 transistor,
1 x 2N3904 transistor,
1 x BAT 85 Schottky diode,
1 x red LED, 1 x 470 k
Ω
resistor, 1 x 100 k
Ω
resis-
tor, 1 x 47 k
Ω
resistor,
1 x 22 k
Ω
resistor,
1 x 6.8 k
Ω
resistor,
1 x 1 k
Ω
resistor,
2 x 220
Ω
resistors,
2 x 10 μF electrolytic
capacitors, 1 x breadboard,
1 x 9V battery with clip
connector
Fig. 2.42:
Active 8.5V battery
monitor
Experiment
An electronic active battery monitor provides information about the status of the monitored battery at any
time. Our circuit here shows the following behaviour:
Battery voltage indicator LED
steady lit, if greater than 8.5 V up to a maximum of 9 V
flashing, if greater than 7.0 V and less than 8.5 V
not illuminated, if less than 7.0 V
You could monitor for example the 9V battery used in this circuit. This makes a lot of sense for experiments
that need to run safely at a voltage from 7 V onwards.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.42.
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...
