Elenco Projects 306-511 - Manual (Page 17)

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Project #328
OBJECTIVE: To learn the principle of an SCR.
In this circuit, the 6-volt bulb (L2) will not light until the SCR (Q3) is
triggered. Turn on the slide switch (S1) and the bulb will not light. Now
press the press switch (S2) to light the bulb. The bulb will stay lit until
the slide switch is turned off. To protect the SCR, a current limiting 1k
Ω
resistor (R2) is placed in series with the gate.
SCR 6V Bulb
Project #327
OBJECTIVE: To change the direction of current flow using a
motor.
Set the meter (M2) to the LOW (or 10mA) setting. A motor generates
a current when it rotates. The rotation of the motor determines the
direction current flows. Quickly spin the motor (M1) clockwise with
your hand; the meter deflects to the right. Now spin the motor
counterclockwise, and the meter deflects to the left.
Meter Deflect
by Motor