Scr 2.5V Bulb; Scr & Motor - Elenco Electronics Snap Circuits Instruction Manual

Project #318
Project #319

SCR 2.5V Bulb

OBJECTIVE: To learn the principle of an SCR.
This circuit demonstrates the principle of the SCR (Q3). The SCR can
be thought of as an electronic switch with three leads:
cathode, and gate. Like a standard diode, it permits current flow in
only one direction. It will only conduct in the forward direction when
triggered by a short pulse or steady voltage applied between the gate
and cathode terminals. One set of batteries powers the lamp, the
other is used to trigger the SCR.
Turn on the switch (S1) and the bulb (L1) should not light. Now press
the press switch (S2); the SCR turns on and lights the bulb. To turn
off the bulb you must turn off the slide switch (S1).
SCR & Motor
OBJECTIVE: To activate a motor using an SCR.
In this circuit, the gate is connected to the battery through resistor R2.
When the switch (S1) is turned on, it triggers the gate, the SCR
conducts, and the motor (M1) spins. The motor continues to spin until
the switch is turned off.
anode,
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