Operational Amplifier
An operational amplifier (op amp) is an amplifier circuit with a differential input, in other words it amplifies the voltage difference between its two inputs. The open-loop gain of an op amp is typically very large so normally, it's configured with negative feedback to reduce the gain. More ...
Integrated Circuit Photoresist Process
The semiconductor photolithography process involves coating the substrate with A light-sensitive chemical layer called photoresist. Light is projected through a mask onto the substrate causings photoresists to react chemically. More ...
Electromagnetic Devices
Electromagnetic devices work based on the relationship between electrical current and a magnetic field. They are used to control valves, cooling and heating systems, relays, and electric motors. More ...
Magnetism
Magnetism is the force exerted by magnets when they attract metals or attract and repel each other. More ...
Transforming Sources for Circuit Analysis
Kirchhoff's laws and Ohm's laws can get pretty laborious when you're analyzing complex circuits. Through a transformation technique, you modify a complex circuit so that in the transformed circuit, the devices are all connected in series or in parallel. After the transformation, you no longer need to systematically apply Kirchhoff's laws. More ...
Alternating Current
With DC (Direct Current), electric current flows in only one direction. With AC (Alternating Current), current direction reverses periodically. More ...
Inductors in Series and Parallel
Inductances in series add like resistances in series. The total value is the sum of the individual values. Inductances in parallel values add up like the values of resistors in parallel. The reciprocal of total inductance is the sum of reciprocals of all the individual inductances. More ...
Inductive Reactance
The opposition that the coil offers to ac is called inductive reactance. Like resistance, reactance is measured in ohms. Unlike resistance, reactance changes with frequency. And in an Inductor, the Voltage leads the Current by 90 degrees. More ...
Junction Field Effect Transistor (JFET)
A Junction Field Effect Transistor (JFET) consists of a channel and a pn junction. The gate controls the conductance of the channel. A JFET is a voltage controlled device, therefore no current flows into the gate. More ...
Direct Current
The nucleus of an atom is relatively heavy, so electricity primarily involves the flow of electrons. The nucleus of an atom generally doesn't move much. More ...
Light Emitting Diode (LED)
An LED is a diode that converts electrical current directly into light and therefore it is more efficient than other sources of light which convert some energy into heat. When electrons recombine with holes in the depletion region they release energy in the form of light photons. More ...
Planar Integrated Circuit Fabrication
The key unit process steps in IC fabrication, include oxidation, photolithography, etching, ion implantation, and metallization. Here, we describe the oxidation steps. More ...
RMS Used in AC Circuit Analysis
Because the value of an AC signal is continuously varying, it would be difficult to use formulas such as ohms law. In the specific case of a sine wave, the Root Mean Square (RMS) of the wave is used instead. More ...
Magnetism
Electric currents and magnetic fields are closely related. Whenever an electric current flows a magnetic field accompanies the current. When a wire is coiled up, the resulting magnetic flux becomes more concentrated. More ...
