voltajallika

Voltajallikas is a device or system that provides a controlled electrical potential difference across its terminals to drive current in an electrical circuit. In theory an ideal voltajallikas maintains a fixed voltage regardless of the current drawn; in real life, practical sources have finite internal resistance and current limits, and their output can vary with load, temperature, and age.

Voltajallikas can be classified by type and mode of operation. Independent voltajallikas supply power without external control, examples being batteries, mains power supplies, and bench power supplies. Dependent (or controlled) voltajallikas are used in circuit models to simulate a voltage that depends on other circuit quantities, such as a voltage-controlled voltage source. Voltajallikas can deliver direct current (DC) or alternating current (AC); DC sources include chemical cells and regulated DC power supplies, while AC sources derive from the mains or from signal generators. Regulated supplies may be fixed or adjustable in voltage, and can be linear or switching (switched-mode) regulators.

In circuit design and testing, voltajallikas are used to power components, generate test signals, or serve as the Thevenin equivalent of a larger network. Their performance is described by open-circuit voltage, short-circuit current, internal resistance, and stability over time and temperature. Safety considerations include proper insulation, isolation from hazardous voltages, overcurrent protection, and adherence to rating limits.

Common applications include electronics prototyping, laboratory experiments, consumer electronics testing, and industrial control systems.