voolallikas

Voolallikas is the Estonian term for a device or circuit that delivers a defined electric current to a load. In English usage, this is known as a current source. A current source is designed to keep the output current roughly constant over a range of load voltages, within specified limits, making it useful for applications that require a stable current rather than a stable voltage.

There are two broad categories: ideal current sources, which are purely theoretical and would provide a constant current regardless of any load or supply conditions, and practical current sources, which are implemented with real components and have finite output impedance, a maximum compliance voltage, and some error that varies with temperature and supply variations. The key performance parameters of a practical voolallikas include the output current value, the compliance voltage (the maximum voltage across the load for which the current remains constant), load regulation (how the current changes with load), and the temperature coefficient.

Common implementations of practical voolallikas include transistor-based circuits, op-amp based current regulators with a sense resistor, current mirrors in integrated circuits, and switched-mode constant-current supplies used in LED drivers and battery charging. In many designs, the goal is a high output impedance so that the current remains stable as the load changes, while keeping the noise and drift within acceptable limits.

Applications for voolallikas span LEDs, precision measurement equipment, battery charging circuits, laboratory test setups, and any scenario requiring a controlled current source. Designers must consider factors such as power dissipation, footprint, noise, and stability when selecting or designing a voolallikas for a given use case.