Maker Factory ELECTRONICS EXPERIMENTS BOX Manual page 85

Circuit 62: DC-DC converter 9V to 75V
Setup information
Install the two transistors, the diode and the three resistors as shown in Fig. 2.62. Next install the ceramic
capacitor, the electrolytic capacitor and the fixed value inductor. It is important to ensure that the electro-
lytic capacitor has a dielectric strength of 160V.
The thirteen jumper wires come next. Check the placement on the board again and only then connect the
battery.
Experiment
This circuit is used to convert a larger DC voltage to a smaller one. The two transistors ensure that strong
current pulses are sent through the fixed value inductor. This results in a very high induction voltage, which
charges the electrolytic capacitor C2 after rectification with D1. There then the highly-transformed output
voltage is available. In our present circuitry the unregulated output voltage is at 75V. The voltage is detected
by a multimeter in a measuring range of 200V.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.62.
Components required:
2 x 2N3904 transistors,
1 x 1N4148 silicon diode,
1 x red LED, 1 x 1 kΩ resis-
tor, 1 x 10 kΩ resistor,
1 x 22 kΩ resistor,
1 x 220 μH fixed induct-
ance, 1 x 1 nF ceramic
capacitor, 1 x 10 μF/160V
electrolytic capacitor,
1 x breadboard,
1 x 9V battery with clip
connector
Fig. 2.62: DC-DC converter 9V
to 75V
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