Constant Voltage Source - Maker Factory ELECTRONICS EXPERIMENTS BOX Manual

2.91 Constant voltage source

Circuit 195: constant voltage source
Setup information
Install the transistor, the diode and the two resistors as shown in Fig. 2.195 followed by the four jumper
wires. Check the placement on the board again and only then connect the battery.
Experiment
Our circuit ensures a constant voltage at the output, even if load resistance and thus current draw changes
greatly. Output voltage is approximately 1.2V if the load resistance value ranges between 100 Ω and 10 kΩ.
You can measure the voltage at the output using a multimeter.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.195.
220
Components required:
1 x 2N3904 transistor,
1 x red LED, 1 x 2.2 kΩ
resistor, 1 x resistor (see
Experiment for value),
1 x breadboard, 1 x 9V bat-
tery with clip connector
Fig. 2.195: constant voltage
source