ELECTRONIC FORMULAS

ELECTRONIC FORMULAS Ohm`s Law Formulas for D-C Circuits. E ’ IR ’ P ’ PR P ’ I2R ’ EI ’ E2 Ohm`s Law Formulas for A-C Circuits and Power Factor. P P Z P ’ I2 Z cos1 ’ IE cos1 ’ E2 cos1 I cos1 cos1 In the above formulas 1 is the angle of lead or lag between current and voltage and cos 1 = P/EI = power factor or pf. Active power (in watts) P R Apparent power (in volt&s) EI Z Note: Active power is the "resistive" power and equals the equivalent heating effect on water. Voltage/Current Phase Rule of Thumb Remember "ELI the ICE man" ELI: Voltage (E) comes before (leads) current (I) in an inductor (L) ICE: Current (I) comes before (leads) Voltage (E) in a capacitor (C) Resistors in Series Rtotal ’ R1 % R2 ’ R3 % ... Two Resistors in Parallel Rt ’ R1 %RR2 Resistors in Parallel, General Formula Rtotal ’ 1 1 % 1 % 1 %... 1 2 3 Resonant Frequency Formulas *Where in the second formula f is in kHz and L and C are in microunits. f ’ 1 , or f ’ 159.2( L ’ 1 , or L ’ 25,330( C ’ 1 , or C ’ 25,330( 2B LC LC 4B f C f C 4B f L f L Conductance G ’ 1 (for D&C circuit) G ’ R (for A&C circuit) R %X Reactance Formulas XC ’ 2BfC C ’ 2BfXC XL ’ 2BfL L ’ 2Bf Impedance Formulas Z ’ R2%(XL&XC)2 (for series circuit) Z ’ RX (for R and X in parallel) R2%X2 Q or Figure of Merit Q ’ XL or XC R 2-7.1 Frequency Response DC Inductor * Pass Capacitor * Block Resister Attenuate "Cartoon" memory aid DC Blocked DC Passes Low Freq Attenuate * Attenuate * Attenuate High Freq Passes High Block Pass Attenuate * Attenuation varies as a function of the value of the each device and the frequency Sinusoidal Voltages and Currents High Freq Blocked Peak Effective value = 0.707 x peak value [Also known as Root-Mean Square (RMS) value] Half Cycle Average value = 0.637 x peak value Effective Average TIME Peak value ˆ Effective value = 1.414 x effective value = 1.11 x average value Three-phase AC Configurations Wye (Y) or Star Delta (120E phase difference between each voltage) If the connection to a three phase AC configuration is miswired, switching any two of the phases will put it back in the proper sequence. Electric power for ships commonly uses the delta configuration, while commercial electronic and aircraft applications commonly use the wye configuration. Color Code for House Wiring: Black or red White Green or bare PURPOSE: HOT NEUTRAL (Return) GROUND Color Code for Chassis Wiring: Red White Black Color Code for Resistors: First and second band: Third band Fourth band (and third band # of zeros if not gold/silver) Multiplier Tolerance 0 Black 1 Brown 2 Red 3 Orange 4 Yellow 5 Green 6 Blue 7 Violet 8 Gray 9 White .1 Gold .01 Silver 5% Gold 10% Silver 20% No color The third color band indicates number of zeros to be added after figures given by first two color bands. But if third color band is gold, multiply by 0.1 and if silver multiply by 0.01. Do not confuse with fourth color-band that indicates tolerance. Thus, a resistor marked blue-red-gold-gold has a resistance of 6.2 ohms and a 5% tolerance. 2-7.2 ... - tailieumienphi.vn