Posts tagged ‘TRIAC’

Teardown and Modification of an Electrophoresis Power Supply

Electrophoresis power supplies are commonly found in biology and other life sciences laboratories. These power supplies are usually capable of supplying high voltages and high currents required for gel electrophoresis–a method used for separating DNA, RNA and other protein fragments based on their size and charge. There are many used electrophoresis power supplies out there in the second hand market and can be bought quite cheaply. I am curious whether these electrophoresis power supplies are suitable for electronics lab use as a lab grade high voltage power supply can be quite expensive. So I recently picked up one from eBay to take a look.

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Dual Purpose Spot Welder With Pulse Duration Control

I had wanted to make a spot welder for a while. Most of the DIY spot welders use a momentary switch the primary side of the microwave oven transformer (MOT). Due to the simplicity of this design, it is very simple to make. This design however, has some inherent safety issues as the momentary switch is typically within reaching distance of the operator (unless a foot switch is used) and inadequate insulation could increase electric shock risk. Further more, the current flowing through the primary winding can significantly exceed the current rating of the switch and cause the switch to fail. Due to the inductive nature of the winding, the switch can sometimes arc over and pose significant risk to the operator. Continue reading ‘Dual Purpose Spot Welder With Pulse Duration Control’ »

On RMS Voltage Measurement

Just because you are using a true RMS multimeter does not automatically mean you should always trust the readings of your measurements. In fact, most true RMS multimeters can only offer reliable readings under certain conditions. In this post, I will examine some of the pitfalls in RMS voltage measurements and show you some concrete examples on how RMS readings can sometimes be misleading. Continue reading ‘On RMS Voltage Measurement’ »

A High Current TRIAC Controller Using Arduino

One of the goals in my previous timer project was to achieve the ability to control multiple electronic devices using the precise time signal generated by the RTC chip (bq3287). For electronic devices using up to a couple of amperes, a relay should be more than capable to handle the load. But for high voltage and high current home appliances such as water heaters (typically 240V, 20 to 30 A), the relay solution becomes much more expensive and less reliable. Continue reading ‘A High Current TRIAC Controller Using Arduino’ »