Find out what the role of a power source is in a circuit. Learn about different power sources. Answer the questions.
Electric current is the directed movement of charge carriers. This raises a legitimate question: what makes charge carriers move? Nothing starts moving without a reason, not even charge carriers. The answer is actually already in the electrostatics chapter - charge carriers are moved by electric force, and the current source in the circuit is responsible for this.
A power source could be two large bodies with opposite charges. If they are connected by a wire, an electric current is generated for a short time. Unfortunately, this is not a very practical power source. The charges of the bodies quickly equalize and the current subsides. A good power source works as a so-called charge pump, which constantly “pushes” and “pulls” charge carriers through wires and electrical devices. The energy required for this work is taken from external forces, for example, from mechanical movement (wind generators, water or steam turbines), chemical reactions (batteries, accumulators) or the energy of light particles or photons (photocells, solar panels).
|
|
|---|---|
| Keemilistes vooluallikates, patareides ja akudes saadakse voolu tekitamiseks vajalik energia keemilisest reaktsioonist. Näiteks autoakus, mis on odav, lihtne ja töökindel vooluallikas, reageerivad metalliline plii ja pliioksiid väävelhappega. | Sellel pildil on elektrigeneraator, millega saab tekitada tavalist, seinakontaktis olevat võrgupinget. Energia saadakse siin kütuste põlemisest, kui sisepõlemismootor ajab ringi elektrigeneraatorit. |
|
|
|---|---|
| Elektroonikas kasutatavad vooluallikad võivad välja näha ka sellised. Pildil kujutud vooluallikas saab oma energia pistiku kaudu teiselt vooluallikalt ja toimib siis ka ise vooluallikana, millel on teistsugused, konkreetsele rakendusele sobivamad omadused. | Selliseid me nimetame tavaliselt toiteplokkideks. Tegemist on jällegi vooluallikaga, mis saab oma pinge seinakontaktist ning toimib siis elektroonikaseadmetele sobiva vooluallikana. |
