Passives Education

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 (Figure below) and 1 wavelength (Figure below) frequencies: Source sees open, same as end of half

The electrons of different types of atoms have different degrees of freedom to move around. With some types of materials, such as metals, the outermost electrons in the atoms are so loosely bound that they chaotically move in the space between the atoms of that material by nothing more than the influence of room-temperature heat energy. Because these virtually unbound electrons are free to leave their respective atoms and float

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

Given two lengths of metal wire, which one will have the least electrical resistance: one that is short, or one that is long? Assume all other factors are equal (same metal type, same wire diameter, etc.).

The Functionality of Diode Polarity Being able to determine the polarity (cathode versus anode) and basic functionality of a diode is a very important skill for the electronics hobbyist or technician to have. Since we know that a diode is essentially nothing more than a one-way valve for electricity, it makes sense we should be able to verify its one-way nature using a DC (battery-powered) ohmmeter as in Figure below.

Identify which trigonometric functions (sine, cosine, or tangent) are represented by each of the following ratios, with reference to the angle labeled with the Greek letter “Theta” (Θ): X R = X Z = R Z =

In this section, we'll be looking at RC and RL circuits. RC and RL circuits are nothing more than applications for resistors, inductors, and capacitors. We will primarily look at RC circuits since they are more commonly used and especially they're widely used with computers circuits and digital circuits which will be our focus. RL will be presented, but it will be in an abbreviated form. Characteristics with sine wave

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

Try out our Resistor Color Code Calculator in our Tools section. Standard Resistor Values and Color Components and wires are coded with colors to identify their value and function. The colors brown, red, green, blue, and violet are used as tolerance codes on 5-band resistors only. All 5-band resistors use a colored tolerance band. The blank (20%) “band” is only used with the “4-band” code (3 colored bands + a blank “band”). Example #1

No text on electrical metering could be called complete without a section on bridge circuits. These ingenious circuits make use of a null-balance meter to compare two voltages, just like the laboratory balance scale compares two weights and indicates when they’re equal. Unlike the “potentiometer” circuit used to simply measure an unknown voltage, bridge circuits can be used to measure all kinds of electrical values, not the least of

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

In very simple, qualitative terms, rate the impedance of capacitors and inductors as “seen” by low-frequency and high-frequency signals alike: Capacitor as it “appears” to a low frequency signal: (high or low) impedance? Capacitor as it “appears” to a high frequency signal: (high or low) impedance? Inductor as it “appears” to a low frequency signal: (high or low) impedance? Inductor as it “appears” to a high frequency signal: (high or

The smaller the wire, the greater the resistance for any given length, all other factors being equal. A wire with greater resistance will dissipate a greater amount of heat energy for any given amount of current, the power being equal to P=I2R. Dissipated power in a resistance manifests itself in the form of heat, and excessive heat can be damaging to a wire (not to mention objects near

When calculating the power dissipation of resistive components, use any one of the three power equations to derive the answer from values of voltage, current, and/or resistance pertaining to each component: This is easily managed by adding another row to our familiar table of voltages, currents, and resistances: Power for any particular table column can be found by the appropriate Ohm’s Law equation (appropriate based on what figures

Let’s analyze a simple series circuit, determining the voltage drops across individual resistors: Determine the Total Circuit Resistance From the given values of individual resistances, we can determine a total circuit resistance, knowing that resistances add in series: Use Ohm’s Law to Calculate Electron Flow From here, we can use Ohm’s Law (I=E/R) to determine the total current, which we know will be the same

Pure resistive AC circuit: resistor voltage and current are in phase. If we were to plot the current and voltage for a very simple AC circuit consisting of a source and a resistor (Figure above), it would look something like this: (Figure below) Voltage and current “in phase” for resistive circuit. Because the resistor simply and directly resists the flow of electrons at all periods of time, the waveform for

Let’s take the same components for our series example circuit and connect them in parallel: (Figure below) 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:

Pure resistive AC circuit: voltage and current are in phase. If we were to plot the current and voltage for a very simple AC circuit consisting of a source and a resistor, (Figure above) it would look something like this: (Figure below) Voltage and current “in phase” for resistive circuit. Because the resistor allows an amount of current directly proportional to the voltage across it at all periods of time,

Designing Wire Resistance Conductor ampacity rating is a crude assessment of resistance based on the potential for current to create a fire hazard. However, we may come across situations where the voltage drop created by wire resistance in a circuit poses concerns other than fire avoidance. For instance, we may be designing a circuit where voltage across a component is critical, and must not fall below a certain limit. If

In simple reactive circuits with little or no resistance, the effects of radically altered impedance will manifest at the resonance frequency predicted by the equation given earlier. In a parallel (tank) LC circuit, this means infinite impedance at resonance. In a series LC circuit, it means zero impedance at resonance: However, as soon as significant levels of resistance are introduced into most LC circuits, this simple calculation for resonance becomes