3
Don’t Make a Sound
Use the circuit from Project 60, but now place a 3-snap wire and the
LED (D1) as “shorting bars” under the paper sheet as shown on left.
Setup: Player 1 sets the “Quiet Zone” by placing the 3-snap wire
and the LED (D1) under the paper on columns 2, 3 or 4, leaving only
one open. Player 2 must NOT know where these “shorting bars” are
located under the paper.
Both Player 1 and Player 2 are given 10 points. The object is for
Player 2 to guess the location of the “Quiet Zone” by placing the paper
clip at positions X, Y, or Z and pressing the press switch. If Player 2
places the paper clip on the correct column, and a sound plays when
he presses the press switch, this means he has not found the “Quiet
Zone” and he loses 1 point. He has three (3) tries to nd the zone on
each turn. Each time sounds are made he loses a point.
Player 2 then sets the 2, 3 or 4 side and player 1 starts searching. Play
continues until one player is at zero points and makes sound during
that players turn.
Discover the Diode
Diodes are electronic components that allow current to ow in only one
direction, blocking it in the other. The red LED (D1) is a special diode
that can emit light, and the transistor (Q1) can also be used as a pair
of diodes.
Turn on the slide switch (S1), the lamp (L1) will be bright and the
LED (D1) will be lit. The NPN transistor (Q2) is used here as a diode,
allowing the batteries to charge up the 470 mF capacitor (C5) and light
the LED.
Turn off the slide switch, the lamp will go dark immediately but the LED
will stay lit for a few moments as capacitor C5 discharges through it.
The transistor/diode isolates the capacitor from the lamp.
Project 61
Project 62
Paper sheet
to hide
position of
shorting bar
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