Subelement E: Digital Logic— Topic 34: Logic Gates
Question 3-34E6
Element 3 (GROL)Which of the following logic gates will provide an active high out when both inputs are active high?
Explanation
An AND gate is the correct choice because its fundamental operation dictates that its output will be active high (logic '1') *only if* all of its inputs are simultaneously active high. This behavior is precisely what the question describes.
Conversely:
* A **NAND** gate provides an active *low* output when both inputs are active high (it's the inverse of an AND gate).
* A **NOR** gate provides an active *low* output if *any* of its inputs, including both, are active high.
* An **XOR** (exclusive OR) gate provides an active *low* output when both inputs are the *same* (either both high or both low).
Understanding these basic logic gate functions is crucial for designing and troubleshooting digital circuits common in amateur radio equipment, such as frequency counters, control systems, and data encoders/decoders.
Related Questions
3-34E4 What is a characteristic of a NOR gate?3-34E5 What is a characteristic of a NOT gate?3-35E1 In a negative-logic circuit, what level is used to represent a logic 0?3-35E2 For the logic input levels shown in Figure 3E12, what are the logic levels of test points A, B and C in this circuit? (Assume positive logic.)3-35E3 For the logic input levels given in Figure 3E13, what are the logic levels of test points A, B and C in this circuit? (Assume positive logic.)