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Q & A
What does the inverter DC-AC use for?
The inverter DC-AC is a equipment to convert DC power as battery, solar power ... AC power used for the appliances electrical equipment or other applications.
What does the Uninterruptable Power Supply (UPS) use for?
Uninterruptable Power Supply (UPS) are supplied devices electricity continuity and stability for load. A typical UPS including battery and charger in a shell machine. There is kinds have batteries outsite for convinient to replace vehicles and storage.
What's the difference between the type of true sine wave DC-AC inverter and the type of simulation (modified) sine wave inverter?
The type of simulation(modified) sine wave inverter DC-AC is cheap but there are many limitations when using. This kind is not effective because of the high consumption of electricity and generates high noisy(nhiễu hài cao), making some electrical equipment is not used. Standard true sine wave DC-AC inverter is designed to improve performance, anti-noise and satisfy all kinds of electrical equipment. It means that Standard true sine wave DC-AC inverter overcome all weak point of mdified (simulation) sine wave inveter.
Has true sine wave inverter AC-DC been used for medical equipment?

For all kinds of medical equipment, oxygen machine air filter ... you must use the true sine wave AC-DC inverter type. Modified sine wave inverter AC-DC type does not AST company check with all kinds of medical equipment. Therefore, it is not sured to work with all these kinds of devices.

When using the modified sine wave inverter AC-DC type, why are there the noise on the sound system?
Some normal sound systems types dose not often has anti-noise circuit. So, when using the modified sine wave inverter DC-AC type, it was high noisy(nhiễu hài cao) make a sound. These categories requires to use true sine wave AC-DC inverter type.
Should we use true sine inverter or modified sine inverter AC-DC?
Depending on type of devices that we use to choose appropriate and effective type of inverter. - The devices work well with modified sine inverter AC-DC type such as lights burned fibers, computers, Coffee machines, ink jet printer, television, video head ... - The device does not work well modified sine inverter AC-DC type such as digital equipment, the engine controllers, medical equipment, telecommunications equipment, lights with adjust brightness, system stereos ...
Why not use metered multi (multi-meter) when measured conversion of DC-AC type sine simulation?
Voltage is the value of (RMS: Root Mean Square), which means the average value of voltage in a cycle. This value for the sine wave form is the standard voltage value for the top two levels of root 2 (= URMS UPEAK / √ 2). Meanwhile, the sine wave form simulation this value is not true anymore. Some metered multi (multi-meter), designed to measure the RMS value of the sine wave form of the standard that is not accurate for other types of waves. At the voltage measurement is wrong, less than 2% to 20% compared with the correct voltage.
How to select an AC-DC inverter with the suitable power?
The fastest answer is in total all powerof all electrical equipments, then buy a AC-DC inverter with the power that is greater than 30%. However, there are also some electrical equipment such as TV, refrigerator, microwave oven ... with the big power to boot (power surge), requiring AC-DC inverter must have more power. AST company has designed many types of AC-DC inverter to solve this request. Because of variety of devices, each has its own requirements so they usually choose to buy the type of AC-DC inverter which has a higher power. On the other hand, battery must also provide enough energy for a boot and then wires must also bear with the variable current when booting but without depreciate voltage too much.
How to determine the power of a microwave oven?
When buying a microwave oven, people are normal interested in how much useful power that was printed on the pack the. But they don’t care about real consumption power from the electric grid. Therefore, a microwave oven with 600W in the packaging will consume about 1200W which was in the back of the machine shell.
Battery cables are large size during AC wires are small type only. Why?
Power P is calculated by voltage U multily with current I, (P = U x I). So, when the voltage is hight, current is not high. Averagely, when using 12V DC, the current is greater than 24 times compare with current when using 220V AC from grid. Main reason makes wires hotter is curent; it is not voltage. That is reason why people transmit voltage on the grid up to thousands voltage (high voltage). When you need high current you have to reduce resistance of wires. The larger size wires the smaller resistance and otherwise. A noteworthy is the average distance from battery to AC-DC inverter (length of wires). The lengther of the wires, the larger of resistance and otherwise
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