Potencia de circuitos, inducción y movimiento de partículas cargadas
GRE Subject Test · GRE Physics Tema 14 6:14 Narración en inglés · Subtítulos en inglés + 中文 quemados en pantalla
Capítulos
Transcripción
A resistor in a parallel branch sees the branch voltage, which can differ from the battery voltage because another resistor is in series.
并联支路中的电阻承受的是支路电压，由于另有电阻串联，它可能与电池电压不同。
This topic solves resistor networks, separates r m s from peak values, applies flux linkage and Lenz's law, and balances the forces on charged particles in fields.
本主题求解电阻网络，区分有效值和峰值，应用磁通链和楞次定律，并平衡带电粒子在场中所受的力。
For steady ideal resistor circuits, series resistances add and parallel conductances add.
对于稳态理想电阻电路，串联电阻相加，并联电导相加。
Reduce a network while preserving which nodes share the same voltage.
在约简网络时，需保持哪些节点具有相同电压的特性。
With a 24 V source, a 2 Ω series resistor and parallel 3 Ω and 6 Ω branches, the parallel equivalent is 2 Ω.
若电源为二十四伏，串联电阻为二欧姆，并联支路分别为三欧姆和六欧姆，则并联等效电阻为二欧姆。
Total current is 6 A, branch voltage is 12 V and branch currents are 4 A and 2 A.
总电流为六安培，支路电压为十二伏，各支路电流分别为四安培和二安培。
The current through every component is not necessarily the total current; verify Kirchhoff current and voltage sums after reduction.
流经每个元件的电流不一定等于总电流；约简后请验证基尔霍夫电流与电压求和。
For a sinusoidal current, I equals I max sine of omega t minus phi, and I r m s equals I max over the square root of 2.
对于正弦电流，I 等于 I max 乘以 ωt 减 φ 的正弦，有效值电流等于 I max 除以根号 2。
A series R L C circuit has an impedance magnitude equal to the square root of R squared plus the square of omega L minus 1 over omega C, and an average dissipated power of I r m s squared R, which equals V r m s times I r m s times cosine phi.
串联 RLC 电路的阻抗大小等于 R 的平方加上 ωL 减 ωC 分之一的平方，再开平方；平均耗散功率等于有效值电流的平方乘以 R，也等于有效值电压乘以有效值电流再乘以 cos φ。
Ideal inductors and capacitors exchange stored energy with zero average dissipation.
理想电感和电容只交换储存的能量，平均耗散为零。
If the r m s current is already given, do not insert another factor of one half.
若已给出有效值电流，不要再乘一个二分之一。
An ideal rectifying diode conducts in its forward direction and blocks in reverse; a suitably oriented series diode clips the negative half of a sinusoidal resistor voltage; it does not create a full-wave rectifier by itself.
理想整流二极管正向导通、反向截止；方向合适的串联二极管会削去电阻上正弦电压的负半周，但它本身不能构成全波整流器。
Magnetic flux is the integral of B dot dA, or B A cosine theta for a uniform field with theta measured from the area normal.
磁通量是B点乘dA的积分，或对于均匀场为B乘以A乘以cos theta，其中theta从面积法向量起算。
Faraday emf is negative N d Phi by d t.
法拉第电动势等于负N乘以Phi对t的导数。
For changing perpendicular field and fixed loop geometry, its average magnitude is N A absolute value of delta B over delta t.
对于变化的垂直磁场和固定的回路几何形状，其平均大小为N乘以A乘以delta B的绝对值除以delta t。
Determine the sign or current direction using opposition to the flux change, not opposition to the field itself.
确定符号或电流方向时，应依据对磁通量变化的阻碍，而非对磁场本身的阻碍。
The magnetic field at the centre of one circular loop is mu zero I over 2 R, obtained from Biot Savart: every element contributes in the same axial direction.
单匝圆形回路中心的磁场为mu零I除以2R，由毕奥萨伐尔定律得出：每个元贡献均沿同一轴向方向。
An N turn compact coil multiplies this result by N.
N匝密绕线圈将此结果乘以N。
For a nonrelativistic charge with velocity perpendicular to a uniform B, the magnetic force, the size of q times v B, provides the centripetal force m v squared over r.
对于速度垂直于均匀磁场 B 的非相对论电荷，磁力大小为 q 的绝对值乘以 v B，提供向心力 m v 平方除以 r。
Thus r equals m v over the size of q times B, and the cyclotron angular frequency is the size of q times B over m, independent of speed in this approximation.
因此 r 等于 m v 除以 q 的绝对值与 B 的乘积，回旋角频率等于 q 的绝对值乘以 B 再除以 m，在此近似下与速度无关。
Charge sign sets the rotation direction.
电荷符号决定旋转方向。
A deuteron has approximately twice the proton mass and the same charge, while an alpha particle has four times its mass and twice its charge; their frequencies are each half the proton value.
氘核质量约为质子的两倍、电荷相同，而 α 粒子质量为质子的四倍、电荷为两倍；它们的频率都是质子值的一半。
In crossed E and B fields, undeflected motion requires opposite electric and magnetic forces, and v equals E over B.
在正交的电场和磁场中，不偏转运动要求电场力与磁场力方向相反，且 v 等于 E 除以 B。
Check vector directions before using this magnitude.
使用这一大小关系之前先检查矢量方向。
A 24 volt source drives 2 ohms in series with parallel 3 and 6 ohm branches.
24 伏的电源驱动一个 2 欧的串联电阻，以及并联的 3 欧和 6 欧两条支路。
The parallel pair is one over the sum of one third and one sixth: 2 ohms.
并联部分等于三分之一与六分之一之和的倒数：2 欧。
The total resistance is 2 plus 2, or 4 ohms, so the source current is 24 volts over 4 ohms: 6 amperes.
总电阻是 2 加 2，即 4 欧，所以电源电流等于 24 伏除以 4 欧：6 安。
The parallel pair carries 6 amperes through 2 ohms, so the branch voltage is 12 volts, not the battery's 24.
并联部分有 6 安电流流过 2 欧，所以支路电压是 12 伏，而不是电池的 24 伏。
The 6 ohm branch carries 12 volts over 6 ohms: 2 amperes.
6 欧支路的电流是 12 伏除以 6 欧：2 安。
The 3 ohm branch carries 4 amperes, and the two branch currents add back to the 6 ampere source current.
3 欧支路的电流是 4 安，两条支路电流相加回到电源的 6 安。
A square N-turn loop of side a moves at speed v out of a uniform field B normal to its plane.
一个边长为a的N匝正方形线圈，以速度v垂直于其平面方向移出均匀磁场B。
Its total resistance is R.
线圈总电阻为R。
While one edge is crossing the straight field boundary, find the emf magnitude, current and required pulling force at constant speed.
当一条边跨越直线磁场边界时，求恒定速度下的感应电动势大小、电流及所需拉力。
Verify mechanical input power equals resistor power.
验证机械输入功率等于电阻消耗功率。
Neglect inductance.
忽略电感。
Flux linkage changes at rate N B a v, so the magnitude of E equals N B a v and I equals N B a v divided by R.
磁链变化率为N B a v，因此感应电动势的绝对值等于N B a v，电流I等于N B a v除以R。
The N edges still in the field give an opposing force F equals N I a B, which is equal to N squared B squared a squared v divided by R.
仍在磁场中的N条边产生反向力F等于N I a B，即N平方B平方a平方v除以R。
F v equals N squared B squared a squared v squared divided by R, which equals I squared R; external work supplies the resistor heat.
F v等于N平方B平方a平方v平方除以R，也等于I平方R；外力做功提供电阻发热。
Lenz's law sets the force opposite motion.
楞次定律规定力的方向与运动方向相反。
Award flux rate, emf current, force, power check and direction.
评分点包括磁通变化率、电动势/电流、力、功率验证及方向。
These results hold only during boundary crossing.
这些结果仅在边界穿越期间成立。
Do not apply battery voltage to every branch or halve an rms-current power again.
不要将电池电压施加到每个支路，也不要再次减半均方根电流功率。
Flux angle uses the area normal; a selector also needs opposing force directions.
磁通角使用面积法向量；选择器还需要方向相反的力。
root mean square: Square root of the mean squared value, used for effective AC current or voltage.
均方根，简称RMS。 这是均方值的平方根，用于有效交流电流或电压。
flux linkage: Sum of magnetic flux through a coil’s turns.
磁通链定义为穿过线圈各匝的磁通量之和。
Retrieve the meanings without reading the definitions, then change a parameter in the original transfer and test the limiting case.
在不阅读定义的情况下回忆其含义，然后改变原始传递中的一个参数并检验极限情况。