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1. PCB resistor element
PCB resistor element is a current limiting element. When the pcb resistor is connected to the circuit, the current through the branch connected to it can be limited.
Its resistance value is fixed and generally has two pins. An ideal pcb resistor is linear, that is, the instantaneous current passing through the resistor is proportional to the applied instantaneous voltage.
The resistance value of a resistor element is generally related to temperature, material, length, and cross-sectional area.
Its basic principle is based on Ohm's law, that is, V=IR is satisfied between current I and voltage V. The resistance here is used to represent the blocking process of the resistor to the current.
A pcb resistor whose resistance value cannot be changed is called a fixed resistor. A resistor whose resistance value is variable is called a potentiometer or a variable resistor.
A two-terminal device that has a definite functional relationship between the terminal voltage and the current and reflects the ability to convert electrical energy into other forms is represented by the letter R, and the unit is ohm Ω.
Actual devices such as light bulbs, heating wires, resistors, etc. can all be represented as resistor elements.
2. Parameter characteristics
Nominal resistance and its allowable deviation:
The design resistance marked on the resistor with numbers or color codes, in units of ohms ((\Omega)), kiloohms ((k\Omega)), megaohms ((M\Omega)), etc.
The allowable deviation is the maximum allowable deviation between the actual resistance and the nominal resistance, expressed as a percentage, commonly used are (\pm5%), (\pm10%), (\pm20%), etc.
Rated power:
The maximum power allowed to be dissipated by the resistor when it is continuously working at the rated temperature (maximum ambient temperature).
The maximum working voltage is also specified for each resistor, that is, when the resistance is high, even if the rated power is not reached, it cannot be used exceeding the maximum working voltage.
Load characteristics:
When the working ambient temperature is lower than the rated temperature, the resistor cannot be used exceeding its rated power. When it exceeds the rated temperature, the load power must be reduced.
Resistance temperature coefficient:
Within the specified ambient temperature range, the average relative change in resistance for every temperature change (1℃), expressed in (ppm/℃).
pcb resistor
3. Classification of pcb resistor elements
Classification by volt-ampere characteristics:
Linear resistors, at a certain temperature, their resistance remains almost unchanged and is a certain value; nonlinear resistors, the resistance changes significantly with the current (or voltage), and its volt-ampere characteristics are a curve.
Classification by material:
Wirewound resistors, made of high-resistance alloy wire wound on an insulating skeleton, coated with a heat-resistant glaze insulation layer or insulating paint on the outside;
Carbon composite resistors, made of carbon and synthetic plastic pressed;
Carbon film resistors, made by depositing crystalline carbon on a ceramic rod skeleton;
Metal film resistors, using vacuum evaporation to evaporate alloy materials on the surface of the ceramic rod skeleton;
Metal oxide film resistors, depositing a layer of metal oxide on the insulating rod.
Classification by use:
General, precision, high frequency, high voltage, high resistance, high power and resistor network, etc.
4 Application of resistor elements
Current limiting:
Protect other components in the circuit to prevent overcurrent. For example, a resistor is connected in series in an LED circuit to limit the current passing through the LED to prevent damage.
Filtering:
Pcb resistors, in combination with capacitors or inductors, can form filters that filter out unwanted signals.
Here are some of the key benefits of using embedded pcb resistors:
1. Save Space and Weight
Components embedded in printed circuits do not require additional space like standard components, so they can save weight and space in printed circuits.
2. Improve Printed Circuit Reliability
Embedded pcb resistors are more reliable because they are not subject to external factors that can cause physical damage or affect their performance. There is no need to use solder joints that are prone to wear over time, which improves reliability and helps extend the overall life and durability of electronic devices.
3 Reduce Circuit Crosstalk
The use of embedded pcb resistors helps reduce unnecessary interference between adjacent PCB signal tracks that can cause signal corruption, especially in high-speed digital circuits and high-frequency applications.
pcb resistor
4. High Power Handling/Enhanced Performance
Integrating pcb resistors within the printed circuit board substrate allows for efficient heat dissipation and higher power handling capabilities compared to traditional surface mount resistors. Connecting components directly to the printed circuit provides greater electrical stability and reduces heat generation, so embedded pcb resistors are particularly suitable for applications involving high power loads.
5. Increased frequency
Embedded resistors are manufactured using special production techniques to ensure high accuracy and stability of resistance values. This means they can transmit signals more efficiently at high frequencies, which is critical for applications that require precise and stable resistance performance.
6. Cost-effectiveness
While the design process of embedded pcb resistors may require an initial investment, the significant savings in production and assembly costs over the entire product life cycle are very considerable.