In electronic circuit design,resistanceDiversion and pressure division are very basic and important concepts. Reasonable calculation of shunt and voltage divider resistors can not only ensure the stable operation of the circuit, but also effectively protect components and improve overall performance. This article will systematically introduce the resistance calculation formulas of shunt and voltage division to help readers deeply understand and flexibly apply this knowledge.
1. Basic concept of shunt resistorShunt resistors are often used to measure current or implement current distribution. It is connected in parallel in the circuit, allowing part of the current to pass through the resistor, thereby achieving the purpose of shunting. The resistance of the shunt resistor is generally small to reduce the voltage drop in the circuit.
2. Calculation formula of shunt resistanceThe calculation of the shunt resistance is based on Ohm's law and the current distribution principle. Assume that the total current is I, the total resistance is R, and the voltage when the total current passes through is U, then the shunt resistance Rs and the main resistance Rm satisfy:
\[ I = I_m + I_s \]
\[ U = I_m \times R_m = I_s \times R_s \]
Therefore, the calculation formula of shunt resistance is:
\[ R_s = \frac{I_m}{I_s} \times R_m \]
Among them, I_m is the current on the main resistor, and I_s is the current on the shunt resistor.
3. Basic concepts of voltage dividing resistorsA voltage dividing resistor is a technique that proportionally distributes the total voltage in a circuit to each resistor by connecting multiple resistors in series. Voltage dividers are widely used in analog signal conditioning, sensor signal acquisition and other fields.
4. Calculation formula of voltage dividing resistorThere are two series resistors R1 and R2, the total voltage is V, and the total current is I, then:
\[ V = I \times (R_1 + R_2) \]
The voltage V2 across R2 in the voltage divider is:
\[ V_2 = I \times R_2 = V \times \frac{R_2}{R_1 + R_2} \]
Therefore, the calculation formula of the voltage dividing resistor is:
\[ V_{out} = V_{in} \times \frac{R_2}{R_1 + R_2} \]
This is also the most commonly used partial pressure formula.
5. Calculation of multi-stage voltage dividing resistorsWhen multiple voltage outputs are required, multi-level voltage division can be achieved through multiple series resistors. The calculation formula for each node voltage is:
\[ V_{n} = V_{in} \times \frac{\sum_{i=n+1}^N R_i}{\sum_{i=1}^N R_i} \]
Among them, N is the total number of series resistors, R_i is the resistance value of the i-th resistor, and V_n is the voltage of the n-th node.
6. Precautions for practical application of shunt resistorsIf the resistance of the shunt resistor is too large, the circuit voltage may drop, affecting normal operation; if the resistance is too small, the current measurement may be inaccurate. In addition, the power consumption of the shunt resistor also needs to be considered, and a resistor with an appropriate power level should be selected to prevent overheating damage.
7. Error and adjustment of voltage dividing resistorIn practical applications, the tolerance of resistor values will lead to voltage division errors. To improve accuracy, resistors with low error and high stability should be selected. In addition, by adjusting the resistor value ratio, the required output voltage can be achieved.
8. Combined application of shunt and pressure dividerIn complex circuits, shunts and voltage dividers are often used in combination. For example, a current measurement circuit requires both a shunt resistor to measure the current and a voltage divider resistor to adjust the signal voltage to achieve accurate signal collection.
9. Calculation tools and software assistanceIn modern design, many circuit design software (such as Multisim and Altium Designer) have integrated shunt and voltage divider resistor calculation modules to help engineers complete the design quickly and accurately and reduce human calculation errors.
Shunt and voltage divider resistor calculations are core fundamentals in electronic circuit design. Mastering its calculation formulas and application skills can effectively improve the performance and stability of the circuit. This article starts from the basic concepts of flow and pressure division, and introduces various calculation formulas and practical application considerations in detail, hoping to provide readers with practical reference and guidance. When designing a circuit, only by combining theory and actual conditions and rationally selecting resistance parameters can the ideal circuit effect be achieved.
