Snap Circuits 750-in-1 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 100Ω 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.

Turn the slide switch (S1) on and the display (D7) does not light. Turn S1

off and then press the press switch (S2) and still the display does not light.

Turn S1 on and press the press switch down. Now, the LED and the letter

“H” light.

A B Q D7

0 0 0 –

1 0 0 –

0 1 0 –

1 1 1 “H”

AND Gate