Why does a resistor with a very small resistance value turn on? What is the function of the connecti

How small are you talking about? No matter how small it is, as long as there is a resistance value, it can be turned on, and if it is too small, it is equivalent to a wire. If you are talking about zero resistance resistance, then the effect is as follows:

1.There is no function in the circuit, just on the PCB for reasons such as convenient debugging or compatible design.

2.It can be used as a jumper, if a certain section of the line is not used, the resistor can be directly not pasted (without affecting the appearance).

3.When the parameters of the matching circuit are uncertain, 0 ohms are used instead, and when the actual debugging is done, the parameters are determined, and then the specific value of the component is replaced.

4.When you want to measure the current consumption of a certain part of the circuit, you can remove the 0ohm resistance and connect the ammeter, which is convenient for measuring the current consumption.

5.When wiring, if it is really impossible to disburse, you can also add a 0 ohm resistor.

6.Under high-frequency signals, it acts as an inductor or capacitor. (related to the characteristics of external circuits) inductance, mainly to solve EMC problems. Such as between ground and ground, power supply and IC PIN.

7.Single-point grounding (refers to protective grounding, working grounding, and DC grounding being separated from each other on the equipment and becoming independent systems. ）

8.Fuse effect.

9.Analog ground and digital ground single point grounding.

Resistor, which can be throughput. What is the specific role depends on the circuit **, generally it is the current limiting effect to prevent some components from burning out.

On-resistance and contact resistance are both forms of resistance, but they have different definitions and applications.

On-resistance refers to the resistance encountered by the current passing through the conductor and is an impediment to the flow of current in a circuit. The on-resistance is determined by factors such as the material, geometry, length, and cross-sectional area of the resistive element itself. In a circuit, the resistive element transmits the current through the conductor, and the resistance of the conductor also has a certain effect on the circuit, which is the on-resistance.

Contact resistance refers to the resistance encountered by the passage of current on the contact surface, which is the impediment to the flow of current in the contact circuit. The contact resistance is mainly determined by the material, shape, pressure, temperature, etc. of the contact surface. The effect of contact resistance on a circuit is mainly the voltage drop generated at the contact point, which leads to the loss of current.

As a result, on-resistance and contact resistance are very different in terms of concept and application. On-resistance is the characteristic of the resistive elements in a circuit, which affects the performance of the entire circuit; The contact resistance is the characteristic of the current flow on the contact surface, which mainly affects the performance of the contact point.

Summary. On-resistance and internal resistance are not the same concept, and there is a difference between them. On-resistance refers to the resistance formed by the conduction of components in a circuit under certain conditions, such as the application of voltage or current.

In other words, on-resistance refers to the resistance of a conductor in a circuit to the passage of electric current. In general, the smaller the on-resistance, the easier it is for the circuit to pass current. Internal resistance, on the other hand, refers to the resistance that exists inside a power supply, which causes the voltage output of the power supply to decrease.

In other words, internal resistance refers to the resistance that a power supply itself produces when it supplies current. Generally speaking, the smaller the internal resistance, the more stable the output voltage of the power supply, and the easier it is for the circuit to obtain a stable voltage. Therefore, although both on-resistance and internal resistance are related to the resistance in the circuit, their definition and role are different.

On-resistance and internal resistance are not the same concept, and there is a difference between them. On-resistance refers to the resistance formed by making the components in a circuit conductive under certain conditions, such as when a voltage or current is applied. In other words, on-resistance refers to the resistance of a conductor in a circuit to the passage of electric current.

In general, the smaller the on-resistance, the easier it is for the circuit to pass current. Internal resistance, on the other hand, refers to the resistance that exists inside a power supply, which will cause the voltage output of the power supply to decrease. In other words, internal resistance refers to the resistance that a power supply itself produces when it supplies current.

Generally speaking, the smaller the internal resistance, the more stable the output voltage of the power supply, and the easier it is for the circuit to obtain a stable voltage. Therefore, although both on-resistance and internal resistance are related to the resistance in the circuit, their definition and role are different.

Given the fixed voltage, do you need to use on-resistance or internal resistance to calculate the current?

If you know a fixed voltage and need to calculate the current, you usually need to use the on-resistance in the circuit. Because the on-resistance refers to the resistance of the conductor in the circuit to the passage of current, it can help us estimate the amount of current generated in the circuit at a given voltage. The internal resistance refers to the resistance generated by the power supply itself, which mainly affects the stability of the output voltage of the power supply, and is generally not directly used to calculate the current.

Of course, in some cases, such as when considering the influence of the internal resistance of the power supply, it may be necessary to consider the effect of both the on-resistance and the internal resistance.

Is the input voltage and output voltage the same for the driver IC?

Not necessarily. The input voltage and output grip voltage of the driver IC are usually different because they are designed to control the voltage or current of other devices. The input voltage of the driver chip is usually the same as the supply voltage of the system bench, while the output voltage depends on the needs of the controlled device.

For example, the driver IC that drives the LED usually has a coarse high-voltage input in the low-voltage segment and a high-voltage output. Therefore, the difference between the input and output voltages depends on the application and design requirements.

Resistance has limited current action, shunt effect, voltage division effect and voltage reduction effect. The resistance of a conductor to an electric current is called the resistance of the conductor.

Equivalent resistance refers to the total resistance value of a single resistor in a circuit in place of all resistors. In a circuit, there will always be resistance present in the circuit due to the presence of various electronic devices. In practice, it is often necessary to calculate the total resistance in a circuit, which requires the use of a formula for equivalent resistance.

When there is only one resistor in a circuit, the equivalent resistance of the fiber is the resistance value of the resistor itself. For series circuits, i.e., circuits in which resistors are connected together one after the other, their total resistance is equal to the sum of the resistance values of each resistor; For parallel circuits, i.e., circuits where resistors are connected to the circuit at the same time, the total resistance is equal to the reciprocal of the sum of the reciprocal values of each resistor.

When there are multiple parts in a circuit that are connected in series and in parallel, they need to be reduced to an equivalent resistor and then calculated using the above formula. Specifically, for some common circuit combinations, the corresponding equivalent resistance formulas can be used to calculate. Equivalent resistance is very important for the design and analysis of circuits, and it is important to grasp the formula of equivalent resistance and its application.

Applications of Resistors:

1. In the current limiting circuit.

Adding resistors to a circuit can reduce the current in the circuit, which can prevent the components from being overloaded or burned out. For example, in an LED circuit, a suitable resistor can be connected in order to limit the current of the LED.

2. In the step-down circuit.

Adding a resistor to a circuit can reduce the voltage in the circuit. For example, in a CPU power supply circuit, a suitable step-down resistor can be connected in order to limit the voltage. Adding resistors to the circuit can be ancillary.

For example, in an audio circuit, in order to increase the sound effect of the speaker, the overall circuit characteristics of the audio output can be changed by adjusting the resistance of the resistor.

3. Vertical luggage in the voltage divider circuit.

Adding a set of resistors to a circuit can divide the voltage into different proportions. For example, in an analog circuit, in order to reduce the output voltage of the amplifier, the voltage of the input signal can be reduced by adding a voltage divider resistor. Adding resistors to the circuit can provide protection from overheating or damage to the components.

For example, in automotive circuits, to prevent over-discharge or short-circuit of the battery.

It has been clearly written in the text description that the use of 12V direct current requires a series of about 2 ohms of resistor.

The following is the wiring schematic, please follow it to wiring:

<> precautions: The power of the voltage regulated power supply should be at least 50W;

2. Each 10W LED should be connected in series with a 2 ohm resistor, and the power is 2W;

3. The positive and negative poles of LED can not be mistaken (see the diagram of "Polarity of LED");

4. The shell is recommended to use aluminum or copper heat sink of high-power LED bracket with fins, and the surface area of the heat sink is 500 square centimeters for 10W high-power LED lamp beads, and it is necessary to connect the flat heat sink with high thermal conductivity on the bottom surface of the LED bracket to coat the thermal conductivity grease;

5. When soldering, please note that it is best to choose a constant temperature soldering iron, the soldering temperature is below 260, and the time of contact between the soldering iron and the LED pad is not more than 3s.

Resistance is a property of the conductor itself, which is related to the material, length, cross-sectional area and temperature of the conductor, and has nothing to do with whether or not the conductor has an electric current and the magnitude of the current that passes

Therefore, choose D