Elenco 130-in-1 Electronics Playground - Manual (Page 124)

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Here’s a DC-DC converter circuit; it can make 5VDC
from 3VDC. Assemble the experiment, set the switch
to position A, and see how this circuit works.
The schematic shows how it works. IC 1 is an
oscillator; its output controls transistor Q1. Self-
induction of the transformer coil generates a high
voltage current. Diode D1 rectifies this voltage and
passes on a high DC voltage current. IC 2 is a
comparator that examines the voltage. When the
input voltage to IC 2 is more than 5V, the LED lights.
How does turning the control affect the circuit? The
control is used as a fixed resistor of 50k
Ω k , so turning
the control has no effect.
Notes:
EXPERIMENT #104 DC-DC CONVERTER
Wiring Sequence:
3-134
5-47-130
26-67-72-81
28-69-90-92-94
31-64
33-76-83-86-93-91-70-106-116-48-120
46-71-75
89-88-63-131
84-87-65
85-66-115-129
82-68-105
119-124-135
122-132
Schematic