→ Коллоквиум 1 Часть 5 → Начать обучение / Скачать MP3 карточки

Вопрос		Ответ
What type of resistor is called a rheostat? начать обучение		A two-terminal variable resistor is called a rheostat.
What is a rheostat used for? начать обучение		It is used to control the current in a circuit.
How does a rheostat vary the value of current? начать обучение		By sliding a contact along a resistive element, it changes the effective length (and thus resistance) in the circuit.
What does it consist of? начать обучение		It consists of a coil of resistive wire and a sliding contact (wiper).
What is the function of the switch? начать обучение		A switch is used to open or close a circuit, thereby controlling the flow of current.
What is a resistor used for? начать обучение		A resistor is used to limit current, divide voltages, and adjust signal levels.
When does the temperature of a resistor rise? начать обучение		Its temperature rises when electrical power is dissipated as heat (P = I²R).
How are resistors rated? начать обучение		They are rated by their resistance value (Ohms), power rating (Watts), and tolerance (%).
What is the difference between a fixed resistor and a variable resistor? начать обучение		A fixed resistor has a single, unchangeable resistance value. A variable resistor (like a potentiometer or rheostat) allows its resistance to be adjusted.

Коллоквиум 1 часть 5