# What is the barrier voltage

## FAQ: What is the electrical voltage?

If there are many positive charges at one point, the electric field emanating from them has an attractive effect on electrons. The negatively charged electrons want to migrate to the positive charges. The more positive charges there are, the stronger the attractive or driving force on the electrons. The "electrical voltage" was defined as a measure for this force or the number of electrical charges.

The electrical voltage indicates how great the difference in electrical charges is between two points. It is measured in "volts" and abbreviated as "V". The symbol for the voltage is "U".

### Why is the electrical voltage important?

In order for an electric current to flow at all, an electric voltage must be present.

### What is polarity or polarity?

The electrical voltage has two poles:

• positive pole, called plus pole
• negative pole, called the negative pole

There is a lack of electrons at the positive pole. This is where the electrons want to migrate. There is an excess of electrons at the negative pole. From there the electrons are repelled.

Note: Sometimes the term polarity is used instead of polarity.

### What is a voltage source?

A voltage source usually means a battery, a generator or a power supply unit. The parts mentioned are voltage generators.
From a theoretical point of view, a voltage generator always consists of a loss-free voltage source (ideal) and a resistor connected in series.
The circuit consisting of the voltage source and internal resistance is the equivalent circuit of a voltage generator. It indicates that losses occur when operating a voltage generator. When the voltage source is loaded, part of the voltage at the internal resistance drops, so that the entire voltage is no longer available at the load.

### What do you have to think of as a voltage source in practice?

In the simplest case, a voltage source is a battery, a power supply unit or a generator. These are electrical energy sources that provide the electrical current.
A voltage source can be thought of as a two-pole component. There is an electrical voltage between the poles or connections. It is also said that there is a voltage applied to it.

### What is the voltage drop?

The voltage of a voltage source is divided among the consumers in the circuit. The partial voltages are referred to as voltage drop, but they have nothing to do with garbage or dirt. This means the drop (reduction) of the source voltage at several consumers connected in series.

### What is DC voltage?

If the polarity of a voltage source always remains the same, then it is a DC voltage source.
Examples of a DC voltage source are a battery, solar cell, a car battery or the accumulator in electronic devices.

### What is AC voltage?

If a voltage source changes its polarity periodically, then it is an AC voltage source. Plus and minus change constantly over time, so that the mean value of the voltage over time is zero. The waveform of an alternating voltage is often a sinusoid, but other forms are also possible.
The number of oscillations of the alternating voltage specified in a frequency.

### What does the frequency indicate?

The frequency describes the number of periodic oscillations per unit of time.

### Where does AC voltage occur?

The mains voltage in our household that is connected to a socket is an alternating voltage.

### How is alternating voltage created?

AC voltage is generated in an alternator. The frequency is proportional to the rotor speed. The rotor is the rotating element in the generator.

### Other related topics:

#### Electronics simple and easy to understand

##### Electronics primer

The electronics primer is a book about the basics of electronics, components, circuit technology and digital technology.

I want that!

### Experience electronics with the "Starter Edition" electronics set

Perfect for beginners and newcomers

• Entry into electronics without prior knowledge
• Quick understanding of components and circuit symbols
• Experiment without a soldering iron: just insert components