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Alphabetical Links to all Tech Circuit™ Blogs and Articles
About the Tech Circuit™ The Tech Circuit’s mission is to continuously improve and maintain the Field Technician’s electrical diagnostics aptitude. The need to provide electrical and electronic related diagnostic solutions in the field has become increasingly unavoidable. Developing an innate understanding of how electricity works greatly empowers you when encountering such scenarios. Below is a […]
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Appliance Technician Cheat Sheets – Full List
Appliance and HVAC Technician Electrical References Below are links to all Appliance Technician Quick-References to date. Feel free to bookmark/share this page or the individual pages below. These are updated as often as needed: 120v Point-to-Point Troubleshooting Cheat Sheet – CLICK HERE 120V Point-to-Point Voltage Pen Diagnostics Cheat Sheet – CLICK HERE 240v Point-to-Point Troubleshooting […]
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Donate to the Tech Circuit
The Tech Circuit’s mission is to better educate Appliance and HVAC Technicians in the area of electrical and electronics diagnostics and repair. There is clearly a need for increased education in this area – and the effort is endless. Although I thoroughly enjoy this mission, it does take time to maintain TechCircuit.org and the Tech […]
How Long does it Take for a Microwave Oven Capacitor to Discharge?
Intro In the 1970’s bleeder resistors on microwave oven high-voltage capacitors started coming into the picture amid safety concerns. By the early 1980’s they started becoming more standard. However, there are plenty of units out there without bleeder resistors, that can hold a charge for a very long time (weeks to even months), due to […]
Five ways to use Ohm’s Law in Appliance Repair
Understanding Ohm’s Law is not only essential for building a strong foundation in electrical theory but also serves as a valuable tool for diagnosing electrical problems. Although many technicians know about Ohm’s Law, some may not use it because they don’t see its relevance or don’t realize when it can be helpful. Ohm’s Law allows […]
How much does the Resistance of an Element Change when Hot?
Most heating elements like those in dryers and ovens utilize a wire made of nichrome, which is an alloy composed of nickel and chromium. It has a very high resistance per foot, a high mechanical strength when hot, and a very high melting point. It also has an extremely low temperature coefficient of resistance (TCR). […]
Thermal Inertia and the Oven Pre-heat
What does the term “Thermal Inertia” have to do with oven pre-heating? Quite a bit actually. You might have noticed that in many electric ranges, both the bake and broil elements work to preheat the oven, but not simultaneously. The Preheating Process For many electric ranges the preheating process involves both the bake and broil […]
Whirlpool Gas Dryer Ignition Circuit Theory and Troubleshooting
This blog will describe step by step, how the standard Whirlpool gas dryer ignition circuit works, along with its common failures and associated diagnostic approaches. Disclaimer: THIS BLOG IS INTENDED FOR APPLIANCE TECHNICIANS AND IS FOR INFORMATIONAL PURPOSES ONLY. ALWAYS FOLLOW PROPER SAFETY PRECAUTIONS WHEN WORKING WITH GAS AND ELECTRICITY. USE THE CONCEPTS DISCUSSED AT […]
Anatomy of a Voltage Source
What is a Voltage Source? Not all voltage sources are created equal. For example, a 12V car battery doesn’t provide enough voltage to electrocute, but plenty enough current to crank a 400A car starter, or to generate a large amount of heat in the case of a short circuit. This would be called a relatively […]
Ohm’s Law – The Most Important Thing you may Never Use
Why do I need Ohm’s Law? Why would Appliance or HVAC Technicians need to use Ohm’s Law in the field? I mean, are they really going to break out the calculator while diagnosing an electrical problem? Probably not. But Ohm’s Law is about a lot more than just finding voltage, current, or resistance. It rather […]
Can I use a 240v Appliance on a 208v System?
Introduction One question I’ve been asked many times in this business is whether a 240v electric appliance can be used on a 208v electrical system. Some apartment buildings use what’s known as 3-phase power, as opposed to the more commonly used single split-phase configuration that comprises the vast majority of residential electric power. This blog […]
Voltage Pen Magic – How to Make the Best of your NCV Tester
Introduction This blog will introduce the many ways that an NCV voltage pen can be used to diagnose electrical circuits. In fact, you might be surprised as to how versatile and useful the voltage pen can actually be. I’ll show you how this simple device can be used to detect Ghost Voltages, detect Compromised Voltage […]
What is a Voltage Divider?
What do floating neutrals, gas dryer valve circuits, Whirlpool electric dryer cool-down circuits, loose terminal block connections, shorted elements, and failing relay contacts all have in common? As the title of this articles suggests – the ever-present voltage divider. They’re everywhere and reside in multiples in every appliance you encounter. They’re not only present in […]