Digital Electronics

Digital circuits are constructed from electronic switches. The switches are either ON or OFF; there are no half-way states so the only voltages present in a digital circuit are the supply voltage V_s (usually +5v) and zero. If a point in a digital circuit is said to be "high" we mean that it is at a voltage very nearly equal to V_s. If the point is said to be "low", it means its voltage is very nearly zero. A high state is represented by "1" and a low state by "0".

Experiments with LOGIC GATES

Logic gates are special switches. One logic gate by itself is not much use. When many gates are connected together, they become very useful; a computer, for example, is basically made from thousands of gates (and other types of special switches).

All the gates in the kit (except the inverters) are two-input gates. The voltage which appears at the output depends on the voltages applied to the two inputs. A truth table is a table which shows how the output is related to the inputs.

• The Inverter
• The AND gate
• The NAND gate
• The OR gate
• The NOR gate
• The EXCLUSIVE OR gate
• Using Logic Gates

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