Maker Factory ELECTRONICS EXPERIMENTS BOX Manual page 82

Circuit 59: DC-DC converter 9V to 35V with LED
Setup information
Install the two transistors, the two diodes and the four resistors as shown in Fig. 2.59. Next, install the
ceramic capacitor, the electrolytic capacitor and the fixed inductance. Make sure that the electrolytic capaci-
tor has a dielectric strength of 160V. The twelve 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 35V. The voltage is detected
by the red LED with larger series resistance, which ensures a lower load.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.59.
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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 47 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. 2.59: DC-DC converter 9V to
35V with LED