John Santiago

When doing circuit analysis, you need to know some essential laws, electrical quantities, relationships, and theorems.Ohm’s law is a key device equation that relates current, voltage, and resistance. Using Kirchhoff’s laws, you can simplify a network of resistors using a single equivalent resistor. You can also do the same type of calculation to obtain the equivalent capacitance and inductance for a network of capacitors or inductors.

Certain electrical quantities, relationships, and electrical units are critical to know when you’re analyzing and characterizing circuit behavior. The following table can help you keep this information straight.

The op amp circuit is a powerful took in modern circuit applications. You can put together basic op amp circuits to build mathematical models that predict complex, real-world behavior. Commercial op amps first entered the market as integrated circuits in the mid-1960s, and by the early 1970s, they dominated the active device market in analog circuits.

Laplace transform methods can be employed to study circuits in the s-domain. Laplace techniques convert circuits with voltage and current signals that change with time to the s-domain so you can analyze the circuit's action using only algebraic techniques. Connection constraints are those physical laws that cause element voltages and currents to behave in certain ways when the devices are interconnected to form a circuit.

A first-order RL parallel circuit has one resistor (or network of resistors) and a single inductor. First-order circuits can be analyzed using first-order differential equations. By analyzing a first-order circuit, you can understand its timing and delays.Analyzing such a parallel RL circuit, like the one shown here, follows the same process as analyzing an RC series circuit.

In circuits, inductors resist instantaneous changes in current and store magnetic energy. Inductors are electromagnetic devices that find heavy use in radiofrequency (RF) circuits. They serve as RF “chokes,” blocking high-frequency signals. This application of inductor circuits is called filtering. Electronic filters select or block whichever frequencies the user chooses.

There are many applications for an RLC circuit, including band-pass filters, band-reject filters, and low-/high-pass filters. You can use series and parallel RLC circuits to create band-pass and band-reject filters. An RLC circuit has a resistor, inductor, and capacitor connected in series or in parallel.You can get a transfer function for a band-pass filter with a parallel RLC circuit, like the one shown here.

Filter circuits (such as low-pass filters, high-pass filters, band-pass filters, and band-reject filters) shape the frequency content of signals by allowing only certain frequencies to pass through. You can describe these filters based on simple circuits. You find the sinusoidal steady-state output of the filter by evaluating the transfer function T(s) at s = jω.

With simple RC circuits, you can build first-order RC low-pass (LPF) and high-pass filters (HPF). These simple circuits can give you a foundational understanding of how filters work so you can build more-complex filters. First-order RC low-pass filter (LPF) Here's an RC series circuit — a circuit with a resistor and capacitor connected in series.