Project 126 fiber fun, Project 128 more fiber fun, Project 127 fiber fun backwards – Elenco Snap Circuits® Deluxe Sound & Light Combo User Manual

Page 71: Project 129 other fiber fun

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Project 126

Fiber Fun

Project 127

Fiber Fun

Backwards

Project 128

More Fiber Fun

Project 129

Other

Fiber Fun

Black

Clear

Clear

Black

Build the circuit as shown.

Place the clear cable holder on

the color LED (D8) and the

black cable holder on the

phototransistor (Q4), then

place the fiber optic cable into

the holders as far as it will go.
Turn on the slide switch (S1).

Light is transmitted from the

color LED, through the fiber

optic cable, to control the NPN

transistor (Q2) and red LED

(D1).
You can replace the red LED

with the white LED (D6), but

the white LED may be dim or

not light.

Use the preceding circuit but

swap the locations of the

phototransistor (Q4) and the

100kW resistor (R5), keep the

“+” side of Q4 in the same

direction. Now the red LED

will be on whenever the color

LED is off.

Build the circuit as shown. Place the

clear cable holder on the color LED (D8)

and the black cable holder on the

phototransistor (Q4), then place the

fiber optic cable into the holders as far

as it will go. For best performance the

fiber optic cable should stand straight up

in the holders, without bending them.
Turn on the slide switch (S1). Light is

transmitted from the color LED,

through the fiber optic cable, to control

the PNP transistor (Q1) and red LED

(D1). The speaker is used to help limit

the current through the color LED,

and will not make noise.
For more fun, swap the locations of

the color LED (D8) and red LED (D1).

You may also replace either LED with

the white LED (D6), but the white LED

may be dim or not light.

Use the preceding circuit but

swap the locations of the

phototransistor (Q4) and the

100kW resistor (R5), keep the

“+” side of Q4 in the same

direction. Now the red LED

will be on whenever the color

LED is on.

SCC-350_Manual_Part_B.qxp 7/25/14 2:05 PM Page 15

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