Transistors, thyristors, capacitors, diodes, microcircuits, etc. - these are the elements that allow you to model and create new projects. So how can variac transformer help in amateur radio? Variac transformer is a laboratory autotransformer, which, using the input voltage, allows you to create the necessary output voltage, of course, within its own technical parameters.
Functional and design features of variac transformer:
1. Smooth voltage regulation (accuracy up to 1 Volt).
2. Sinusoidal output voltage.
3. Liquid crystal indication of output voltage.
4. Reinforced brush assembly.
5. Convenient terminal blocks for network and load connection.
SUNTEK variac transformer - Layout of the main elements
In simple terms, you can set the voltage you need in the network. For example, the situation with a soldering iron. Everyone knows that microcircuits and processors are mostly sensitive to temperature and manufacturers do not recommend heating the soldering iron in this case higher than 230 degrees Celsius. Thus, by lowering the voltage that is supplied to your soldering iron, from 220 volts to 150 volts, for example, you reduce its power and, as a result, its temperature. Also, by returning the regulator knob back, you return the power to the soldering iron.
Suppose you need to check the voltage at the nodal points? According to the diagram, for example, you see what should be 163 Volts, 220 Volts, 196 Volts. Where can you find these transformers? Yes, they are not really needed. Using the variac transformer autotransformer, you can easily set the desired voltage.
But how can all of them choose the right variac transformer model?
After all, there are capacities from 500 W to 60 kW and you can’t make a mistake, because most variac transformers do not have large protections. Let's answer right away: everything is simple here. Each variac transformer has two important parameters:
1. Working range. For example, SUNTEK variac transformer can change the voltage from 0 to 300 Volts, there are variac transformer of other brands that operate in the range up to 250 Volts. It is important to understand that this range is calculated at an input voltage of 220 volts. That is, when the input voltage changes, the output also changes. For example, the input voltage has dropped to 190 Volts and then the SUNTEK variac transformer range (0-300 Volts) will be narrower (0-270 Volts). And if the input voltage is 250 Volts, then the variac transformer range will be 0-330 Volts (but this will already be a dangerous state) Because all manufacturers recommend operating their equipment at the normal voltage of 220 volts.
2. The maximum allowed current. This is such a current, upon reaching which the variac transformer will almost instantly fail. Here is an example. You bought variac transformer 2A 500W. Many will think that they can connect a load of 500 watts. This is not entirely true. The current 2A is a constant, but the power will change. Here is an example, you bought a music center with a power of 400 watts and operating at a voltage of 110 volts. Well, an inexperienced person will buy a 500W variac transformer "with a margin" and will be upset. The more experienced one knows that the current is the power divided by the voltage, in our case it is about 4A. We look at the plate and choose the correct model (for example, variac transformer SUNTEK 1000 VA 4A).
SUNTEK variac transformer
| Model | Power, VA | Current, A |
| Variac transformer SUNTEK 500 VA | 500 | 2 |
| Variac transformer SUNTEK 1000 VA | 1 000 | 4 |
| Variac transformer SUNTEK 2000 VA | 2 000 | 8 |
| Variac transformer SUNTEK 3000 VA | 3 000 | 12 |
| Variac transformer SUNTEK 5000 VA | 5 000 | 20 |
| Variac transformer SUNTEK 7000 VA | 7 000 | 28 |
| Variac transformer SUNTEK 10 kVA | 10 000 | 40 |
| Variac transformer SUNTEK 15 kVA | 15 000 | 60 |
| Variac transformer SUNTEK 20 kVA | 20 000 | 80 |
| Variac transformer SUNTEK 30 kVA | 30 000 | 120 |
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