No matter what the salesperson or spec sheet says, an HVAC system is only as good as the people who install and service them. Though it might sound hard to believe, the number of support calls logged to service HVAC equipment is on the rise and, in many cases, a common culprit can be identified: the variable speed drive.
While much of the world has at least heard the term “transistor” before, their function and importance aren’t exactly common knowledge. Knowledge of thyristors and their purpose is arguably even more vague and yet, both diminutive electrical components are integral to many of the electric-powered devices that are the backbone of our societies and economies.
Though they are not explicitly named for their widespread use, universal motors can, in fact, be found just about everywhere. Open any number of household appliances or industrial machines for example, and chances are you will find a universal motor at its core. But if they aren’t named for the seemingly “universal” applications to which they lend themselves, why are they named as such?
A stepper motor is an electromechanical device designed to convert electrical power into mechanical power. If you aren’t overly familiar with motors, it might be difficult to distinguish a stepper motor from another motor type and, more importantly, appreciate the role they play in industrial and manufacturing settings.
In this article we will be reviewing DC source conversion and understand how it can be useful when analyzing circuits. DC sources are mainly referred to as sources of constant voltages or currents. Hence, we can classify them into two types; DC Voltage Source and DC Current Source, where each source type representation includes an internal resistance “Rint” as illustrated in the figure below.
Magnets are found almost everywhere in our lives. From refrigerator magnets that help hold up calendars, pictures, and grocery lists, to the magnets found in our cars that assist in keeping us safe. But how does it all work? Magnetism is the force that is exerted by magnets and is caused by the motion of electrical charge.
In this article, we’ll talk about the basics of magnetism, what it is, what causes it, and how it appears as an important part of electromechanical systems.
To say that many of the lightweight and inexpensive electronics that we use daily are taken for granted is a bit of an understatement. Much of what we use and enjoy, however, could not have been possible without the development and implementation of the bipolar junction transistor (BJT). Invented in 1947 by William Shockley, BJTs were integral components during the infancy of modern computing technologies, from computer memory to microprocessors and more.
This article is intended to illustrate the steps required for creating a Norton equivalent circuit. All the concepts mentioned here build on the prior knowledge of simplifying circuits.
According to Norton's theorem, any two-terminal circuit, made up of fixed value resistances, of voltage sources, and of current sources, can be replaced by a single current source in parallel with a single resistance which will produce the same effects at the terminals.
Kirchhoff’s voltage law can be used to analyze any electric circuit but when dealing with complex circuits, using Kirchhoff's voltage laws can be difficult. Therefore, it is important for you to learn other network theorems and recognize when to apply them. In this blog, we will be discussing Superposition Theorem. Superposition theorem can be used when trying to analyze a linear circuit with multiple voltage and current sources.
In this blog, we will review the bypass capacitor, its function, and how it is important in an amplifier circuit.
What is a Bypass Capacitor?
A bypass capacitor is added to an amplifier circuit in order to allow AC signals to bypass the emitter resistor. This effectively removes it from the output gain equation resulting in an increase to the amplifiers AC gain.
Used in audio equipment, radio, TV, and computers amplifiers are components that increase or amplify the voltage, current or power of an electrical signal. Almost all electronic circuits and systems use at least one stage of amplification. As engineers and technicians, we should be able to identify different classes of amplifiers.
We all are surrounded by electronic devices including phones, laptops, TV etc, but did you ever wonder what these things are made of. Most people might answer circuits which is correct to a point. A circuit is a closed path that allow electricity to flow from one end to another and made of various individual components such as resistors, capacitors, inductors etc.
Almost every moving device is powered by an electro mechanical system. These systems are present in most electric motors, solenoids and mechatronics. From vehicle power windows and power seats to washers and dryers, many of the products we use in our everyday lives rely on these systems. Here are the three most common electro mechanical systems and devices and how they work.
In this blog, we will review the concept of resistance, resistivity and steps to calculate the minimum cross-sectional area and diameter of any desired conductor.
What is Resistance?
The property of a device or a circuit that opposes the movement of current through it. Resistance is measured in Ohms (Ω). The resistance of any material with a uniform cross-sectional area is determined by the following four factors:
In this blog, we will review the theory of Magnetic Fields and its basic concept. We all know that magnets exert forces on each other and its magnetic force is distributed around. Magnetic field lines are used to describe these forces around the magnet. We understand that magnets have two poles and that depending on the orientation of two magnets there can be an attraction (opposite poles) or repulsion (similar poles).
In this blog we will review the theory of the Air gaps in magnetic circuits. A magnetic circuit is where a magnetic flux is circulated or follow through a closed area or path. An air gap is a non-magnetic part of a magnetic circuits and it is usually connected magnetically in series with the rest of the circuit. This allows a substantial part of the magnetic flux flows through the gap.
In this blog we will review the theory of the Current Divider circuits in a parallel circuit. In a parallel circuit, all the components have their terminals connected together sharing the same two end nodes. This results in different paths and branches for the current to flow or pass along. However, the currents can have different values through each component but the voltage remains the same across two end nodes.
In this blog we will explore Inductance; one of the major properties of an electrical circuit or an electronic device. Inductance is defined as a property of electrical circuit or a device that opposes a change in current. It is important to note that inductance does not oppose the current but rather opposes the change in current flowing within the circuit.
In electronics, filters serve a critical role in many common applications such as audio electronics, radio communications and power supplies. We use filters to block or pass a specific range of frequencies. The filters can be either passive or active. We usually divide filters into four main types, depending on which frequency components of the input signal they pass on to the output signal. The four types of filters are low-pass, high-pass, band-pass, and band-stop.
Radians and angular velocity are terms that are commonly used in AC theory and AC measurement. Most of the electric energy used commercially is generated as Alternating Current (AC). The main reason Alternating Current is used is that alternating voltage may be easily raised or lowered in value.
In this installment of the "Practicing Technician" series we will review the calculation required to determine the resistance of a given conductor. This often overlooked parameter can be important when trying to determine the appropriate wire diameter for a given application. It is also important to consider conductor resistance when examining application efficiency. Lower resistance means lower power dissipation by the conductor.
In this installment of our "Practicing Technician" series, we will once again be working with a circuit reduction technique. This particular technique is quite useful for determining how changes in load conditions can impact on circuit performance. Until now, we have provided reduction techniques that are useful for fixed load circuit analysis. Thevenin's theorem can be used in cases where we want to see how load voltage, current and power are effected by changes in load resistance.
In the fourth part of our series on Tips For Practicing Technicians, we look at a simple technique that can be used to simplify circuit analysis when working with series and parallel RL circuits. One of the issues encountered by technicians who are working with parallel RL circuits is the need to work with values that are the reciprocals of the more commonly used standard units.
This is the third in our series of brief articles discussing important topics relevant to electronics and electromechanical technicians and technician students preparing for today’s workforce. In this series, we will be discussing some everyday skills and topics for practicing technicians, as well as some areas that have been identified as “difficult to understand” by our technician students while performing general circuit analysis.