Many electronic devices require a stable supply of electricity to function properly. The electrical network, generators and chemical batteries alone cannot provide this condition. Therefore, modern electronics are equipped with power supplies, in which there are voltage and current stabilizers.
Voltage stabilizer
Under Art. voltage (U) understand the device, the circuitry of which is assembled in such a way that in automatic mode it allows you to keep the level (U) at the input of the consumer unchanged within the specified limits. Use devices in cases where there is no stable electricity on the power source.
Depending on the type of electricity, appliances are:
- Variable voltage;
- constant voltage.
According to the principle of action:
- compensation type;
- parametric.
With these devices it is impossible to achieve perfect alignment, but only partially smooth out the destabilization.
Current stabilizer
Current stabilizers (I) are otherwise called current generators. Themthe main task is, regardless of what load is connected at the output of the device (meaning the load resistance), to produce a constantly stable current (I). To ensure this condition, all devices without exception have input impedance of large values.
The scope of devices is extensive. They are used in the power circuits of LED lamps, gas discharge lamps and always in chargers where the option of changing the charging current value is used.
As the simplest scheme of Art. the combination is a voltage source plus a resistor. This is the traditional LED power supply scheme. The disadvantage of this technical solution is the need to use a high power source (U). Only this condition allows you to use a high-resistance resistor to achieve the stabilization effect.
Types of stabilizers
Considering voltage and current stabilizers, you need to understand that they are of different types for different kinds of electricity. So, the classification divides them into devices for working in circuits of direct or alternating electricity. According to the principle of obtaining stabilization, there are compensation and parametric schemes.
In parametric type devices, radio elements are used, in which the current-voltage characteristic (CVC) has a non-linear form. So, these elements for working with alternating voltage are chokes with a saturated ferromagnetic core. The issue of direct voltage stabilization is solved by stabistors and zener diodes. The current is stabilized with the help of transistors - field workers and bipolar workers.
Voltage and current stabilizers of compensation type work on the principle of compensation when comparing the actual parameter of electricity with the reference given by a certain node of the device. In such systems there is a feedback through which the control signal comes to the regulating element. Under the influence of a signal, the parameters of the controlled device change in proportion to the change in input electricity, and at the output it remains stable. Compensation devices are of continuous regulation, pulse and continuous-pulse.
Both parametric and compensation voltage and current stabilizers can be characterized by weight, size, quality and energy indicators. Quality stabilizers (U) include:
- coefficient of voltage stabilization at the input;
- internal circuit resistance;
- ripple equalization factor.
For Stabilizers (I):
- coefficient for input (U) current stabilization;
- stabilization factor in the process when the load changes;
- coefficient Art. temperature.
The energy parameters include:
- efficiency;
- the power that the regulating element is able to dissipate.
Adjustable voltage and current stabilizer
To obtain stabilization with the ability to control electrical parameters and a higher coefficient, complex transistorschemes.
The scheme consists of:
- St. current on the transistor VT1. Its task is to provide direct current to the collector, which then goes through the amplifier and to the base of the regulating element.
- Amplifier (I) on a bipolar VTy. This transistor responds to a voltage drop across a resistive divider.
- Regulating element on the transistor VT2. Thanks to him, the output (U) either decreases or increases.
AC voltage stabilizers are used to power household appliances. Standard parameters of such devices:
- Ability to adjust (U) output without distorting the signal.
- Stabilization of a large input voltage spread from 140 to 260 volts.
- High maintenance accuracy (U) with a discrepancy of no more than 2%.
- High efficiency.
- Availability of overload protection circuits.
Current and voltage stabilizer circuits
Parametric device (U), assembled according to a single-stage scheme.
The scheme consists of:
- A zener diode that drops one voltage value regardless of (I) passing through it.
- A quenching resistor where excess (U) is released as current increases.
- Diode acting as temperature compensator.
According to the two-stage scheme.
Such schemes have the best stabilization performance, as they consist of:
- Pre-cascadestabilization, performed on two series-connected zener diodes, where there is also thermal compensation due to the positive and negative temperature coefficients of radio elements.
- Terminal stabilization stage on a zener diode and a quenching resistor, which is powered by the first stage.
Parametric current device on the field device according to the scheme - source-gate shorted.
Since there is no field effect transistor (U) between the source and the gate, it only passes a certain value (I) regardless of input voltage changes. The disadvantage of the circuit is associated with a spread in the characteristics of field workers, which makes it difficult to establish the exact value of the stabilized current.
Parametric voltage regulator with built-in current regulator.
The circuit is a combination of a single-stage voltage regulator, where instead of a damping resistance, a stabilization element (I) is included on the field switch. This design has a greater stabilization factor.
Compensating stabilizer with (U) constant value and regulation in continuous mode.
DIY electricity stabilization device
Modern stabilizing devices are implemented in microcircuits. You can assemble a voltage and current stabilizer with your own hands using the LM317. This is the simplest circuit that does not require adjustment.
Instead of a printed circuit board, you can use a getinax or textolite plate. It is not necessary to etch the tracks. The circuit is simple, so it is more convenient to make the contacts with wire segments.
Conclusion
It is important to know that all control elements in circuits can get very hot, especially microcircuits. Therefore, they must be installed on the radiator.
For reliable protection of household equipment among industrial devices, you can use the Resanta AC voltage stabilizer.
