One of the main problems encounteredBoth experienced and novice lovers of designing electrical and radio equipment, is the power supply. For these needs, and developed such a device as a power source (PI).
When choosing such a device must take into account a numbernecessary factors that are determined by the operating conditions, safety requirements, properties of loads and other. Moreover, it is necessary to take into account the types of such devices as a network power source - it can be powerful, medium power or micro-power.
In the first place you need to turn yourattention to the compliance of the parameters of such a device with the requirements of the device itself. The power source has a number of similar characteristics: current consumption, supply voltage, required (normal or nominal) level for voltage stabilization, acceptable (as well as its minimum and maximum value) voltage ripple level.
Also the power source has some qualities andcharacteristics that directly affect its operation and scope. For example, the presence or absence of a protection system, the mass and dimensions of the device.
Power supply is an integral part of anyelectronic device. The means of both primary and secondary power supply must absolutely meet the necessary required criteria, which are applied both to the equipment as a whole and to its component parts. If a device such as a power supply has some parameters beyond the permissible limits, this can lead to a dissonance in the device and its breakage.
There are several types of network sources of electricity:
- with a capacitor or a quenching resistor (the so-called transformerless);
- linear, which are made according to the classical scheme (transformer-rectifier, then filtering and stabilization takes place);
- pulsed high-voltage and high-frequency;
- pulse secondary (they work according to the scheme of transformer-filter-converter of high frequencies);
- autonomous power sources;
- linear PI.
Linear are the most simple and affordable.for the price for radio amateurs. They are often used in small-sized devices, such as chargers, batteries, power supplies, alarm systems and so on. Also here can be attributed and uninterruptible power supply (UPS).
However, when using current values above one ampere, the efficiency of using such a device as a linear power supply drops sharply for a number of reasons:
- stabilization factor will be unstable due to fluctuations in the mains voltage;
- large currents require the installation of large radiators on regulating transistors and rectifying diodes;
- a deliberately higher voltage will be applied to the input of the stabilizer than any permissible one in case of fluctuations in the network.
Recently, however, pulse converters (secondary), as well as a power source based on high-frequency converters with transformerless inputs, have become quite common.
