Elenco Electronics 202 - Manual (Page 114)

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Project #266
OBJECTIVE: To experiment with oscillator circuits.
This circuit flashes the lamp (L2) and turns the motor (M1) about once
a second. Moving the control lever on the adjustable resistor (RV)
makes these occur more or less often. This works with the fan on or
off the motor.
Nothing happens while the capacitor (C4) charges up through
resistors RV and R4. Then the capacitor discharges in a burst that
lights the lamp and turns the motor.
Motor Oscillator
OBJECTIVE: To experiment with oscillator circuits. OBJECTIVE: To experiment with oscillator circuits.
Now replace the 470 μF capacitor (C5) with the smaller 10μF capacitor
(C3). Now the circuit activates more frequently, but the lamp (L2) is dim
and the motor (M1) jerks.
The adjustable resistor (RV) control works the same way, and the fan can
be on or off the motor.
Replace the 100 μF capacitor (C4) with the larger 470μF capacitor (C5).
Now the circuit activates less often, but the lamp (L2) flash is brighter
and the motor (M1) turns farther. This is due to more capacitance. The
adjustable resistor (RV) control works the same way, and the fan can be
on or off the motor.
You can decrease the frequency of an oscillator circuit by increasing
either the resistance or the capacitance.
Project #267
Motor Oscillator (II)
Project #268
Motor Oscillator (III)
!
WARNING: Moving parts. Do not touch the fan or
motor during operation.
!
WARNING: Moving parts. Do not touch the fan or
motor during operation.
!
WARNING: Moving parts. Do not touch the fan or
motor during operation.