Switches for Low Voltage Circuits

There are many thousand ways of using electric circuits. We are, certainly, unable to list all of them here. In fact, whether our problem is to flesh a minute flashlight or to supply electric energy to a great factory, we make use of an electric circuit. In addition to that it is necessary to know how to control the flow of electric current so that it were suitable for running machinery without being too great or damaging.

The first problem of control is that of switching the current on and off. That is why a switch is always to be inserted in a circuit.

A switch is a device to open or close a circuit or in other words a convenient device to put wires together or to take them apart. Conductors being supported by insulators, the current may be made to flow or to stop the flow. The simplest type of switch is called the single-pole single-throw switch (sec Fig. 10, left).

The single-pole double-throw switch is used to complete one of two circuits or to break both (see Fig, 10),

 The push-button is another type of switch to be considered. This type of switch has two metal springs for conductors. When the pushbutton is pressed, the upper spring comes in contact with the lower spring, making contact or connection complete (see Fig. 13),

There are many other types of switches, for example, a mercury-type switch, a thermostatic switch, and others.

Words and word combinations:

flashlight –проблесковый огонь, фотовспышка

suitable –подходящий

to support - поддерживать, нести, подпирать

to insert –вставлять, включать в цепь

to take apart –

to trace –оставлять след, прослеживать

single-pole single-throw switch –однополюсной

                   одноколенчатый выключатель  

single-pole double-throw switch – однополюсной

                     двуколенчатый выключатель

the upper (lower) spring –верхняя (нижняя) пружина,

mercury-type switch – ртутный выключатель,

thermostatic switch – термостатический выключатель

push-button – кнопка кнопочного управления

Assignment:

I. Find in the text the following words and word combinations:

Не в состоянии составить список всех, необходимо знать, другими словами, устройство, простейший тип выключателя, поэтому, другие виды выключателей, к тому же (кроме),

II. Put ten questions to the text and answer them.

III. Pick up pairs of synonyms out of the words and word combinations, given below.

To supply, to switch on, to break a circuit, to finish, to connect, to stop, to switch off, to provide, device, minute, to turn off, to turn on, instrument, lo open a circuit, to join