Properties of electrical signals

An electrical signal is a voltage or current which conveys information. The term can be used for any voltage or current in a circuit.

The voltage-time graph on the right shows various properties of an electrical signal. In addition to the properties shown on the graph, there is frequency which is the number of cycles per second.

The diagram shows a sine wave but these properties have any signals with a constant shape.

· Amplitude is the maximum voltage reached by the signal.
It is measured in volts, V.

· Peak voltage is another name for amplitude.

· Peak-peak voltage is twice the peak voltage (amplitude).

· Time period is the time taken for the signal to complete one cycle.
It is measured in seconds (s), but time periods tend to be short so milliseconds (ms) and microseconds (µs) are often used. 1ms = 0.001s and 1µs = 0.000001s.

· Frequency is the number of cycles per second.
It is measured in hertz (Hz), but frequencies tend to be high so kilohertz (kHz) and megahertz (MHz) are often used. 1kHz = 1000Hz and 1MHz = 1000000Hz.

frequency = 1

time period

time period = 1

frequency

Mains electricity in the UK and Russia has a frequency of 50Hz, so it has a time period of ¹/₅₀ = 0.02s = 20ms.

Exercise 1. Translate from Russian into English.

1.Постоянный ток всегда течет в одном и том же направлении, но может увеличиваться и уменьшаться.

2. Элементы питания, батареи и стабилизированные источники питания обеспечивают устойчивый постоянный ток, который является идеальным для электронных схем.

3. Источники питания имеют трансформатор, который преобразует сетевой переменный ток в безопасный переменный ток с низким напряжением.

4. Скорость изменения направления переменного тока называется частотой и измеряется в герцах.

5. Период – это время, за которое сигнал завершает один цикл.

Part II

English-speaking Countries

Text 1

London

London is the largest city in Western Europe. About 8 million people live there. It lies on both banks of the Thames.

Photo: The City of London

London is traditionally divided into several parts: the City of London, which is the financial center of the United Kingdom, the West End, which is the area of museums, art galleries, largest department stores, cinemas, and hotels. West End and is associated with wealth and luxury; and the East End, which is the industrial part of London and is very important for the commerce.

Поиск по сайту: