User Manual

Disco Cover
Build the circuit as shown, place of the disco covers on the disco
motor (DM), and turn the slide switch (S1). The speaker (SP2)
makes sound and the disco cover may rotate.
Build the circuit as shown, place one of the disco covers on the disco motor
(DM), and turn on the slide switch (S1). Nothing happens. Push & release
the press switch (S2); the green LED (D2) flashes once, turning on PNP
& NPN transistors (Q1 and Q2), so now the disco motor and the LEDs on
it turn on. The circuit will continue to run until switch S1 is turned off.
Transistors Q1 and Q2 act as a
thyristor bistable switch,
conducting electricity when
their gate (the left side of Q2) is
triggered (by pressing S2), and
continuing to conduct until the
circuit is turned off.
Project 185
Weird
Sound (II)
Use the preceding circuit, but
add the red/yellow LED (D10,
in either direction) across
points A & B.
-70-
Project 187
Thyristor Start Disco Ball
Project 184
Weird Sound
Project 186
Weird
Sound (III)
Use the preceding circuit but
move the red/yellow LED (D10)
from points A & B to points C &
D (in either direction). The LED
will be on level 4, so you need
to stack an extra 2-snap wire
on point C.
SUPPORT BAR
Disco Cover
SUPPORT BAR