What is a level, and how do you understand it?

"Level" is the relative ratio of the amount of electricity at two or more points in a circuit at the same impedance. The amount of electricity here naturally refers to "electric power", "voltage", "current", and multipliers are converted into logarithms, which are expressed as "decibels" and denoted as "db". Respectively, they are written as:

10lg(p2 p lg(u2 u lg(i2 i1) where p, u, and i are electrical power, voltage, and current, respectively. There are two advantages to using "db": one is that it is easy to read, write, and calculate.

If the total amplification of a multistage amplifier is the multiplication of the magnifications of each stage, the addition can be used instead when using decibels. Second, it can faithfully reflect people's perception of sound. Practice has shown that when the number of decibels of sound increases or decreases, the loudness of the human ear also doubles or decreases.

That is, the human ear hearing is directly proportional to the number of decibels of sound power.

The level is generally used to refer to the node voltage state of a digital circuit, such as a 5V digital circuit system, generally voltages higher than 4V (or different devices) are considered high, and voltages below are considered low.

Power refers to the amount of electrical energy consumed per unit time of a circuit or load, and the product of the input voltage and the input current is the input power.

The so-called level refers to the logarithm of the ratio of two powers or voltages, and sometimes it can also be used to express the logarithm of the ratio of two currents. The unit decibel of the level is expressed in dB. There are two types of commonly used levels: power level and voltage level, which can be divided into absolute level and relative level.

When people first learn about "level", they often compare the abstract concept of electricity to the concrete phenomenon of water use. For example, the water flow is specific to the current, the water pressure is like the voltage, and the water resistance is the resistance. Explain the "level" in the same way.

When we say "horizontal", the dictionary explains that it is parallel to the horizontal, or has reached a certain height in some way, and by extension, refers to the conclusion that things are compared under the same bridge.

For example, people often say that Zhang's work is very high, and Li's work level is very poor. You know what that means. That is, "Zhang" refers to the comparison between "Zhang" and "Li". Therefore, using "level" as a metaphor for "level" can make it easier for people to understand.

Level refers to the logarithm of the ratio of two powers or voltages, and can sometimes be used to express the logarithm of the ratio of two currents.

The unit decibel of the level is expressed in dB. There are two types of commonly used levels: power level and voltage level, which can be divided into absolute level and relative level.

To understand what logic levels are about, it's important to first know what the following concepts mean:

1: Input High Voltage (VIH): Ensure that the input of the logic gate is the minimum input high allowed when the input level is high, when the input level is higher than VIH, the input level is considered to be high.

2: Input Low Voltage (VIL): Ensure that the input of the logic gate is the maximum input low allowed when the level is low, when the input level is lower than VIL, the input level is considered to be low.

3: Output high voltage (VOH): Ensure that the output of the logic gate is the minimum value of the output level when it is high, and the level value when the output of the logic gate is high must be greater than this VOH.

4: Output low voltage (vol): Ensure that the output of the logic gate is the maximum value of the output level when it is low, and the level value when the output of the logic gate is low must be less than this vol.

5: Threshold level voltage (VT): Digital circuit chips all have a band threshold voltage, which is the level when the circuit can barely flip the action.

It is a voltage value between the input high voltage and the input low voltage, for the threshold level voltage of the CMOS circuit, it is basically one-half of the power supply voltage value, but to ensure a stable output, it must be required to output high voltage, input high voltage, output low voltage "input low voltage, and if the input voltage is above and below the threshold, that is, the area of vil vih, the output of the circuit will be in an unstable state.

A level is the relative ratio of two or more points of charge at the same impedance. In logic circuits, one of two or more points is specified as the reference, and the ratio greater than 1 is high, and less than 1 is low. Level refers to the relative ratio of the amount of electricity at two or more points in a circuit at the same impedance.

The amount of electricity here refers to the electrical power, voltage, and current. If these two points are two points in the circuit before and after the same signal is processed, then the level is the amplification or attenuation multiplier. In acoustics and signal processing, multiples are converted into logarithms and given a dedicated unit "decibels", denoted as "db".

For the power value: db=10xlog10(a b) where a and b represent the power values participating in the comparison; For field quantities: db=20xlog10(a b)=10 log10(a b) where a and b represent the current, voltage and other field quantities involved in the comparison.

In a logic circuit, one of two or more points of electricity is specified as the reference (logic level), and the ratio greater than 1 is high, and less than 1 is low. To put it simply, it is high above the benchmark and low on the contrary. A level is a dimensionless quantity (a physical quantity that has no units).

Many logic circuit (component) manufacturers will specify a specific range of power values for the output or output at high and low levels, and many people refer to this power value as the level. Although this statement deviates from the original definition of level, it does not affect (contribute) to the application of the concept of level in practical work.