A universal power supply is an indispensable thing that must be present in the workshop of any radio amateur. Test the newly developed circuit, check the device that came to hand, charge the battery, urgently power up some medical device, in which the power supply unit suddenly failed or the batteries simply run out.

But you never know, it may require constant voltage. And it would be good if the value of this constant voltage could be regulated within certain limits, and even better - the presence of a current control unit in the power supply, so that when a certain current value is reached, the voltage would no longer increase, but would be kept at such a level that the in no case would the load current be exceeded. The described needs are fully able to satisfy the laboratory power supply, which is a universal ...

In cities, cable television has almost completely replaced the “wireless” competitors, but there is still a demand for TV antennas. In order to receive on-air TV you need to choose a device suitable for your area in design and range. Especially often this need arises in the countryside and the private sector. In this article we will consider what are the antennas for the TV and how to choose it correctly.

Before moving on to talking about the types of television antennas, it is worth talking about the basic terms that will be used in the article. Repeater - a device that receives and amplifies a radio signal and transmits to its subscribers. People call it a TV tower. Antenna - a device for receiving or transmitting radio waves. Its main task is to convert electromagnetic waves into signals the other way around. It is connected to the receiver, in our case, to the TV ...

Hot water has become the norm in a modern house. In large cities, hot water is supplied centrally, while people in the province have either never heard of or have already forgotten. Even where there is a centralized hot water supply during the period of preventive maintenance, water can be turned off for a period of several days to several months. To create comfortable conditions and not depend on this factor, you need to install a water heater. In this article, we will consider the selection criteria and the design of a storage water heater.

Water heaters are by source of energy: gas, electric, other types of fuel. By type of heating and water movement: Flowing. For example, a gas water heater or an electric flow heater. In them, the water heats up when it flows through the heat exchanger. Cumulative. For example, a boiler, it is a water tank. In them, a certain amount of water is heated gradually. Heating time depends on power ...

To calculate the parameters of the charger for a particular battery, you must first take into account the type and parameters of the battery that you are going to charge with this device. The most important characteristics of a rechargeable battery are: capacity, full charge voltage, maximum allowable charge current, as well as a range of permissible operating temperatures.

Depending on what kind of battery it is, what type of materials it uses - the parameters of the charger should be selected individually. Here we look at lead-acid and lithium-ion batteries, or rather the features of their charging.The truth is that if the battery is always charged correctly, in compliance with the optimal values ​​of voltage and current, then it will retain its capacity for many charge-discharge cycles. Of course, provided that it is also discharged, subject to restrictions ...

If there is a marking on the transformer, then the question of determining its parameters is settled by itself, you just need to drive this data into the search engine and instantly get a link to the documentation for our transformer. However, marking may not be, then we need to calculate these parameters ourselves.

To determine the rated current and power of an unknown transformer by its appearance, it is necessary first of all to understand what physical parameters of the device are determining in this context. And such parameters are primarily the effective cross-sectional area of ​​the magnetic circuit (core) and the cross-sectional area of ​​the wires of the primary and secondary windings. We will talk about single-phase transformers, the magnetic cores of which are made of transformer steel, and are designed specifically for operation from a network of 220 volts 50 Hz ...

Having decided to replace the capacitor on the printed circuit board, the first thing to do is to choose a replacement capacitor. As a rule, we are talking about an electrolytic capacitor, which, due to the exhaustion of its working life, began to create an abnormal mode for your electronic device, or the capacitor burst due to overheating, or maybe you just decided to put the capacitor newer or better.

The parameters of the replacement capacitor must certainly be suitable: its rated voltage should in no case be lower than that of the replaced capacitor, and the capacitance should not be lower, or it may be 5-10 percent higher (if this is permissible in accordance with the known circuit of this device) than it was originally. Finally, make sure that the new capacitor fits the size that its predecessor will leave. If it turns out to be a little smaller in diameter and height - not scary, but if the diameter or height is greater ...

A wide range of products in different price ranges is presented on the market of LED lamps and fixtures. The main difference between devices of low and medium price segments is to a greater extent not in the LEDs used, but in the power sources for them. LEDs work from direct current, and not from the alternating current that flows in the household electrical network, and the reliability of the lamps and the mode of operation of the LEDs are more dependent on the quality of the converter.

In this article, we will look at how to protect LED lamps and extend the life of low-cost models. Everything described below is true for luminaires and lamps. The cheapest LED products use a blanking capacitor as a power source. The principle of its operation is based on the reactance of a capacitor. In simple words, the capacitor in an AC circuit is an analogue of a resistor.Hence the same disadvantages follow. ...

Growing vegetables in a greenhouse requires special attention to all the nuances and conditions. A significant role is played by the temperature of the soil and the environment. Frost is especially dangerous for plants, and if the temperature of the soil drops below the recommended norm, then the seedlings can disappear altogether. Therefore, you need to equip the soil heating system. One of the possible options is heating the greenhouses and soil with a heating cable.

Heating the soil with a cable will help to achieve a larger crop than without it.The optimum temperature is considered to be at the level of 15-25 degrees Celsius. To achieve this temperature, it is necessary to spend 75-100 W / m. In this case, the specified parameters should not be exceeded, since overheating of the root system as well as hypothermia is dangerous. To save the cable, it should be laid only in those places where plants will grow. Warming the soil under paths and walkways is simply meaningless ...