Passives {if 0}- Education

When inductors are connected in series, the total inductance is the sum of the individual inductors’ inductances. To understand why this is so, consider the following: the definitive measure of inductance is the amount of voltage dropped across an inductor for a given rate of current change through it. If inductors are connected together in series (thus sharing the same current, and seeing the same rate of change in current),

By definition, a low-pass filter is a circuit offering easy passage to low-frequency signals and difficult passage to high-frequency signals. There are two basic kinds of circuits capable of accomplishing this objective, and many variations of each one: The inductive low-pass filter in (Figure below) and the capacitive low-pass filter in (Figure also below). Inductive Low-Pass Filter Inductive low-pass filter The inductor’s impedance increases with increasing frequency. This high

On this page, we’ll outline the three principles you should understand regarding parallel circuits: Voltage: Voltage is equal across all components in a parallel circuit. Current: The total circuit current is equal to the sum of the individual branch currents. Resistance: Individual resistances diminish to equal a smaller total resistance rather than add to make the total. Let’s take a look at some examples of parallel circuits that

Passive Devices Components incapable of controlling current by means of another electrical signal are called passive devices. Resistors, capacitors, inductors, transformers, and even diodes are all considered passive devices. Active Devices An active device is any type of circuit component with the ability to electrically control electric charge flow (electricity controlling electricity). In order for a circuit to be properly called electronic, it must contain at least one active device.

The first, and perhaps most important, the relationship between current, voltage, and resistance is called Ohm’s Law, discovered by Georg Simon Ohm and published in his 1827 paper, The Galvanic Circuit Investigated Mathematically. Voltage, Current, and Resistance An electric circuit is formed when a conductive path is created to allow electric charge to continuously move. This continuous movement of electric charge through the conductors of a circuit is called a

Let’s take the same components for our series example circuit and connect them in parallel: Parallel R-L circuit. Because the power source has the same frequency as the series example circuit, and the resistor and inductor both have the same values of resistance and inductance, respectively, they must also have the same values of impedance. So, we can begin our analysis table with the same “given” values: The only

Wiring Color Codes Infographic. Released under the Creative Commons Attribution-ShareAlike License Looking for Wiring & Resistor Calculators? View our Wire & Resistor calculators in our Tools section. Basic Wire Color Code Information by Region Many of the wire identifications standards rely on color codes. Which standard should you be using for your project? It depends on your location, voltage, and other important factors. Note: Older installations may use different color

As we saw with DC measurement circuits, the circuit configuration known as a bridge can be a very useful way to measure unknown values of resistance. This is true with AC as well, and we can apply the very same principle to the accurate measurement of unknown impedances. How Does a Bridge Circuit Work? To review, the bridge circuit works as a pair of two-component voltage dividers connected across the

Resistors vs. Inductors Inductors do not behave the same way as resistors do. Whereas resistors simply oppose the flow of current through them (by dropping a voltage directly proportional to the current), inductors oppose changes in current through them, by dropping a voltage directly proportional to the rate of change of current. In accordance with Lenz’s Law, this induced voltage is always of such a polarity as to try

Continuing in Section 3.3, we're looking at the component resistors. Resistors are fundamental components in electronic circuits. A resistor is constructed to have a specific amount of resistance to current flow. The range of resistors may be from less than one ohm to well over 20 million ohms or 20 mega ohms. Fixed resistors have a single value of resistance but variable resistors can provide different values of resistance. Here have a few

Reactive Power We know that reactive loads such as inductors and capacitors dissipate zero power, yet the fact that they drop voltage and draw current gives the deceptive impression that they actually do dissipate power. This “phantom power” is called reactive power, and it is measured in a unit called Volt-Amps-Reactive (VAR), rather than watts. The mathematical symbol for reactive power is (unfortunately) the capital letter Q. True Power The

While Oersted’s surprising discovery of electromagnetism paved the way for more practical applications of electricity, it was Michael Faraday who gave us the key to the practical generation of electricity: electromagnetic induction. Faraday discovered that a voltage would be generated across a length of wire if that wire was exposed to a perpendicular magnetic field flux of changing intensity. An easy way to create a magnetic field of changing

Introduction Whenever an electric voltage exists between two separated conductors, an electric field is present within the space between those conductors. In basic electronics, we study the interactions of voltage, current, and resistance as they pertain to circuits, which are conductive paths through which electrons may travel. When we talk about fields, however, we’re dealing with interactions that can be spread across empty space. Admittedly, the concept of a �

When using conventional current flow, we can trace the direction of the current in the same circuit by starting at the positive (+) terminal and going to the negative (-) terminal of the battery, the only source of voltage in the circuit. From this, we can see that the current is flowing clockwise, from point 1 to 2 to 3 to 4 to 5 to 6 and back to 1 again. As the current encounters the 5 Ω resistance, voltage

The Inductance Formula Wheeler’s formulas for inductance of air core coils which follow are useful for radio frequency inductors. The following formula for the inductance of a single layer air core solenoid coil is accurate to approximately 1% for 2r/l < 3. The thick coil formula is 1% accurate when the denominator terms are approximately equal. Wheeler’s spiral formula is 1% accurate for c>0.2r. While this is a “round

Standing waves at the resonant frequency points of an open- or short-circuited transmission line produce unusual effects. When the signal frequency is such that exactly 1/2 wave or some multiple thereof matches the line’s length, the source “sees” the load impedance as it is. The following pair of illustrations shows an open-circuited line operating at 1/2 and 1 wavelength frequencies: Source sees open, same as end of half wavelength line. Source sees

This calculator gives the reactance and admittance of an inductor or the inductance given the reactance of an inductor

We're continuing in 7-3 on a discussion concluding capacitors. We're looking at current flow in a capacitive circuit. Even though a capacitor has an internal insulator, and that's going to be right here, current can flow through the external circuit as long as the capacitor is charging and discharging, so as long as it's charging and discharging current can flow. You may recall that in the previous discussion we had

You might have noticed on the table for specific resistances that all figures were specified at a temperature of 20° Celsius. If you suspected that this meant specific resistance of a material may change with temperature, you were right! Resistance values for conductors at any temperature other than the standard temperature (usually specified at 20 Celsius) on the specific resistance table must be determined through yet another formula: The “alpha” (α) constant is

Dielectric strength in kilovolts per inch (kV/in): Material* Dielectric strength ========================================= Vacuum --------------------- 20 Air ------------------------ 20 to 75 Porcelain ------------------ 40 to 200 Paraffin Wax --------------- 200 to 300 Transformer Oil ------------ 400 Bakelite ------------------- 300 to 550 Rubber --------------------- 450 to 700 Shellac -------------------- 900 Paper ---------------------- 1250 Teflon --------------------- 1500 Glass ---------------------- 2000 to 3000 Mica ----------------------- 5000 * = Materials listed are specially prepared for electrical use