Project #640, Strobe light, Project #641 – Elenco Projects 512-692 User Manual
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Project #640
OBJECTIVE: To construct an LED strobe light.
Strobe Light
This is an example of how a large strobe light works. Turn the slide
switch (S1) on and the LED (D2) flashes at a certain frequency. Adjust
the frequency by adjusting the adjustable resistor (RV). Now add
sound by replacing the 100
Ω
resistor (R1) with the speaker (SP). Each
time the LED lights, the speaker sounds.
Project #641
OBJECTIVE: To demonstrate the operations of the AND gate.
AND Gate
In digital electronics, there are two states, 0 & 1. The AND gate performs
a logical “and” operation on two inputs, A & B. If A AND B are both 1, then
Q should be 1. The logic table below shows the state of “Q” with different
inputs and the symbol for it in circuit diagrams.
In the circuit, the S1 & S2 switches represent inputs A & B, and the D7
display represents output Q.
A
B
Q
D7
0
0
0
“L”
1
0
0
“L”
0
1
0
“L”
1
1
1
“H”
A
B
Q
AND Gate