آموزشکده فنی قوچان 

گروه الکترونیک

متون درس زبان فنی –  رشته الکترونیک

مقطع کاردانی پیوسته

مجموعه دوم  :

·     Resistance

·     Capacitors

·     Capacitance and Uses of Capacitors

موحدی – بهمن 89

Resistance

Resistance

Resistance is the property of a component which restricts the flow of electric current. Energy is used up as the voltage across the component drives the current through it and this energy appears as heat in the component.

Resistance is measured in ohms, the symbol for ohm is an omega .
1 is quite small for electronics so resistances are often given in k and M .
1 k = 1000     1 M = 1000000 .

Resistors used in electronics can have resistances as low as 0.1 or as high as 10 M .

Resistors connected in Series

When resistors are connected in series their combined resistance is equal to the individual resistances added together. For example if resistors R1 and R2 are connected in series their combined resistance, R, is given by:

Combined resistance in series:   R = R1 + R2

This can be extended for more resistors: R = R1 + R2 + R3 + R4 + ...

Note that the combined resistance in series will always be greater than any of the individual resistances.

Types of Resistors

The Different Types of Resistors

Resistors ( R ), are the most fundamental and commonly used of all the electronic components, to the point where they are almost taken for granted. There are many different Types of Resistors available to the electronics constructor, from very small surface mount chip resistors up to large wirewound power resistors. The principal job of a resistor within an electrical or electronic circuit is to "resist" (hence the name resistor) or to impede the flow of electrons through them by using the type of material that they are composed from. Resistors can also act as voltage droppers or voltage dividers within

 دانلود در ادامه مطالب

آقای موحدی – بهمن 89