What Are Volts and Why Do They Matter?

Volt, Ampere, Watt, how are these three terms to be understood?

Volts represent the basic unit of voltage, or volts for short. Symbol V.

Named in honor of Italian physicist Volt.

The three most basic units in electricity are voltage (V), current (I), and resistance (r). The units of voltage are volts, the units of current are amps, and the units of resistance are ohms.

Volt: The unit of voltage in V

Ampere: The unit of current in A

Watt: The unit of power in W

Power W=Voltage V*Current A

What Are Volts and Why Do They Matter
What are volts and why do they matter?

How to distinguish the ammeter, voltmeter and ohmmeter in the multimeter?

The ammeter measures current, with the symbol “A”; the voltmeter measures voltage, with the symbol “V” or “kV”; the ohmmeter measures resistance, with the symbol “Ω”

How the photovoltaic effect occurs

1. Photovoltaic effect refers to the phenomenon that light causes a potential difference between different

parts of uneven semiconductor or semiconductor and metal bonding. It is firstly the process of converting photons (light waves) into electrons and light energy into electric energy; secondly, it is the process of forming voltage. With voltage, it is like building a dam. If the two are connected, a current loop will be formed.

2. Photovoltaic materials are materials that can directly convert solar energy into electrical energy. Photovoltaic materials are also called solar cell materials, and only semiconductor materials have this function. Materials that can be used as solar cell materials include monocrystalline silicon, polycrystalline silicon, amorphous silicon, GaAs, GaAlAs, InP, CdS, CdTe, etc. For space there are single crystal silicon, GaAs, InP.

3. Monocrystalline silicon, polycrystalline silicon and amorphous silicon have been mass-produced for the ground. Others are still in development. Currently, efforts are being made to reduce material costs and improve conversion efficiency, so that the electricity price of solar cells can compete with that of thermal power generation, thereby creating conditions for wider and larger-scale applications.

4. The non-electrostatic force of the photoelectromotive force (photocell) comes from the internal photoelectric effect. Under illumination, if the energy of the incident photon is greater than the forbidden band width, the bound valence electrons near the PN junction of the semiconductor absorb the photon energy and are excited to transition to the conduction band. Free electrons are formed, and correspondingly free holes are formed in the valence band. These electron-hole pairs, under the action of the internal electric field, the holes move to the P region, and the electrons move to the N region, so that the P region is positively charged, and the N region is negatively charged, so a voltage is generated between the P region and the N region, It is called photoelectromotive force, which is the photovoltaic effect. Sensitive elements made of photovoltaic special effects include photocells, photodiodes, and phototransistors.

What is the total current in the circuit? What about the current and voltage of each branch?

The total current of the circuit is required, and the total resistance of the circuit needs to be calculated first.

In this circuit, there is a 5-ohm resistor and a 3-ohm resistor in parallel, so first find the parallel resistance of these two resistors, and then add the 10-ohm resistor in series to find the total resistance of the entire circuit, The total current in the circuit can then be obtained by dividing the supply voltage by the total resistance.

Then multiply the total current by the resistance of ten ohms to get the voltage across the resistor, and then subtract ten ohms from the power supply voltage, and the voltage of the resistor can be used to find the voltage of the parallel circuit. With the voltage of this parallel circuit, and then multiplying it by the resistance of three ohms, the current of the resistance of three ohms can be calculated, and then multiplying the voltage of the parallel circuit by the resistance, the current of the resistance of five ohms can be calculated.

Total current i=20/[10+(5 and 3)]=20/[95/8]=32/19 A.

Is the total voltage of a parallel circuit equal to the sum of the voltages of the branches?

The power supply voltage of a parallel circuit is not equal to the sum of the voltages of the branches. In a parallel circuit, the voltages of the branches are equal, and the power supply voltage is equal to the voltage of the individual branches connected in parallel to the power supply.

The voltage of the parallel circuit is equal to the voltage of each branch, and the current of the parallel circuit is equal to the sum of the current of each branch.

Electric Boat Lithium Iron Phosphate Battery Voltage (Volt)

Type Power Nominal Voltage Nominal Capacity

Fishing boat: Electricity: 49.5kWh, nominal voltage 352.8V, nominal capacity 140.4Ah

Speedboat: Power: 92kWh, nominal voltage 655.2V, nominal capacity 140.4Ah

Yacht: Power: 93.5kWh, nominal voltage 345.6V, nominal capacity 270Ah

Sightseeing boat: Power: 62.9kWh, nominal voltage 151.2V, nominal capacity 416Ah

What is the voltage of household appliances?

TV: 110V-250V.

Refrigerator: 160V-265V.

Heating and cooling air conditioner: 150V-265V, constant speed: 185V-265V.

Washing machine: 175V-265V.

At present, there are generally two types of voltages used for indoor electricity in countries around the world:

They are 100V~130V, and 220~240V two types.

100V, 110 ~ 130V are classified as low voltage, such as the United States, Japan, etc. and the voltage on board, so its equipment is designed according to such low voltage, focusing on safety.

Common voltage values

  • The voltage induced by the TV signal on the antenna: about 0.1mV
  • Voltage to maintain human biocurrent: about 1.2mV
  • Alkaline battery nominal voltage: 1.5V [5]
  • Voltage between the two poles of silver oxide battery for electronic watch: 1.5V
  • One lead-acid battery voltage: 2V [5]
  • The voltage between the two poles of the battery of the hand-held mobile phone: 3.7V
  • Human body safety voltage: not higher than 36V [6]
  • Household voltage in Japan and some American countries: 110V
  • Voltage of home circuit: 220V
  • Power circuit voltage: 380V
  • Voltage of trolleybus power supply: 550~600V
  • Working voltage of TV picture tube: above 10kV
  • Grid voltage above the train: 25kV [5]

Voltage between clouds where lightning occurs: up to 1000kV

Is Voltage Dangerous?

The simple answer is NO. Voltage is just pressure and poses no danger. In fact, when you get a spark off your finger from static electricity, the voltage of that spark is usually around 25,000 volts!

We have all seen this sticker but it’s a bit of a misnomer. The high voltage is not dangerous, but the circuit also has a high current which is dangerous. You need both high voltage and current to be dangerous.

Since voltage is only a measurement of pressure, there needs to be enough electrons to flow to be dangerous. With enough pressure and flow (amps) an electrical circuit can become dangerous. Any circuit below 50 volts will not have enough electrical pressure to push enough current through your body to cause harm.

Introduction to the classification of voltmeters

Analog Electronic Voltmeter

The analog electronic voltmeter generally uses a magnetoelectric ammeter head as an indicator. Since the magnetoelectric ammeter can only measure DC current, when measuring DC voltage, it can be directly amplified or attenuated into a certain amount of DC current to drive the pointer of the DC meter head to deflect to indicate its size; when measuring AC voltage, it must pass through AC – DC converter, which converts the AC voltage to be measured into a DC voltage proportional to it, and then measures the DC voltage.

In the analog electronic voltmeter, most of them use the rectification method to convert the AC signal into a DC signal, and then indicate the reading through the DC meter. This method is called the detection method; in addition, there are thermocouple conversion methods and formula conversion methods.

Digital Voltmeter

The digital voltmeter first uses the analog/digital (A/D) conversion principle to convert the measured analog voltage into the corresponding digital quantity, and directly display the measured voltage value in digital form. Compared with the analog voltmeter, the digital voltmeter has the advantages of high precision, fast measurement speed, strong anti-interference ability, high degree of automation, and easy reading.

The most basic and common digital voltmeter is the DC digital voltmeter (DVM), which can measure AC voltage, current, resistance and other electricity with different converters or sensors at its input. It is an essential part of many digital measuring instruments.

Digital Voltmeter
How to measure voltage?
We use a multimeter or voltmeter to measure the voltage of a household circuit or battery. A voltmeter can only measure voltage, but a multimeter can make many other measurements.
How to use a multimeter
A digital multimeter has a red wire (wire) and a black wire (wire).
First, plug the red test lead into the multimeter’s input labeled “V” and the black test lead into the multimeter’s input labeled “COM”. (Here’s how to make sure you’re measuring voltage and not amps or ohms.)
NOTE: Make sure not to reverse the red and black leads (wires), as this may damage or destroy the multimeter.
Next, use the dial in the center of the multimeter to select AC (alternating current) mode or DC (direct current) mode, depending on what you want to measure. (Note: DC represents a straight line with three dots below it, and the wavy symbol represents AC. In addition, some multimeters may use “DCV” for DC voltage and “ACV” for AC voltage.)
DC is used to measure voltage in batteries or small electronic devices, and AC is used to measure voltage in household sockets and large household electronic devices or appliances.
Many DMMs automatically select the range to measure. If you need a different range, check the user manual for the normal voltage of the device you are measuring. Set the range one level above the voltage you are measuring. For example, if you measure a 12 volt battery, you need to turn the dial to 20V (one step above 12).
How to Test a Multimeter on a Battery

To test the multimeter on a battery, touch the metal probe from the red lead on the positive terminal and the metal probe from the black lead on the negative terminal, while holding only the plastic caps of the probes in your hand. If necessary, use the center dial to select the battery voltage range. Check the voltage reading on the display.
NOTE: If your reading is “1” or negative, check the range and make sure your leads are entered correctly.

High Voltage Vs Low Voltage 
high voltage
High voltage long distance power supply. In some applications, such as powering our homes over high-voltage power lines, large amounts of electricity are transmitted over long distances.
The most significant advantage of high-voltage transmission is higher efficiency. When power is transmitted over long distances, energy is lost along the way. High voltage transmission minimizes energy loss from one location to another.
The biggest disadvantage of high-voltage transmission is the possibility of accidents. While high voltage alone is not dangerous, the current flowing through the line is. A good example is a collapsed power cord. Even near live power lines is dangerous because high-voltage electricity can create arcs in the air, causing serious injury or even death.
low voltage
Low voltages are considered voltages below 50V (volts). Standard low voltages are 12V, 24V and 48V. Low voltage wiring does not carry the same current as electrical outlets.
Low-voltage marine battery manufacturers
Keheng Lithium batteries are considered 12 V low voltage batteries but can be connected in series up to 48 V.
A significant advantage of low voltage systems is that they are powered by batteries. Other benefits of low voltage wiring are that it is easy to install and does not require a professional electrician. It is much safer than high voltage wiring, and the wiring requires less insulation.
What is the volt of the battery?
Battery voltage is the amount of potential the battery holds, measured in volts. The voltage of a battery can vary from a few hundredths of a volt to a few hundred volts, depending on the size and construction of the battery.
For simplicity, think of the battery as a pipe. The voltage of this battery is the water pressure in the pipe. It is this pressure that causes the current to flow, powering your device. Let’s look at some standard battery voltages.
Tesla electric car battery voltage
A battery module for a Tesla electric car with a voltage of 21.6 volts. The entire car battery pack is 375 volts.
What happens if the device is connected to the wrong voltage?
Equipment and equipment are designed to function properly at specific rated voltages. Devices connected to the wrong voltage can cause problems ranging from inability to operate to serious consequences such as fire. Let’s look at a few examples:
If you connect a 110-volt (110V) rated appliance to a 220-volt (220V) power source, it will be in an overvoltage condition when it is turned on. This will melt the fuse and damage the device.
If you connect a 220 Volt (220V) device to a 110 Volt (110V) power source, the power will be a fraction of what the device should have when it was turned on. For example, a light may be dim, the motor will not turn or turn very slowly, or the heating element will barely heat. Most likely, these devices simply won’t work.
Volts are essential to modern life
Through the sharing of the above knowledge about volts, volts are very important! The most important thing, however, is to work with their mates, Amps and Watts.
Volts. Amps and Watts have worked together to bring us the joys and conveniences associated with electricity.

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