Category: Tutorial videos

How to charge a LiPo battery

How to charge a LiPo battery with a power supply

How to charge a single cell lithium ion or lithium polymer battery with an adjustable, current limiting bench power supply.

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Battery chemistry

How to choose a battery: A battery chemistry tutorial

There are many different types of rechargeable battery chemistries out there. Li-Polymer, NiCd, NiMH, LiFePO4, lead acid and more. In the first half of this video I give a brief overview of the basic pros and cons of each type of rechargeable battery chemistry and help you choose a battery for your project. Then in […]

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Amp-hour watt-hour battery capacity

Battery amp-hour, watt-hour and C rating tutorial

You may have seen batteries with things like “2000mAh” written on them before. This refers to the capacity of the battery, i.e. how much juice it can hold. In this video I explain Ah (amp-hours), Wh (watt-hours) and C ratings of batteries.

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boost converter

DC-DC Boost converter tutorial

In this tutorial I explain DC-DC boost converters – a type of circuit used to step up voltage in an efficient manner. Towards the end I show how to construct a 50 watt adjustable boost converter circuit. Parts list: LT1370HV: Electrolytic capacitors: Input and output ceramic caps:!?q=UMK325BJ106MM-T Schottky diode: 10uH inductor: […]

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adjustable dc to dc converter

Adjustable switch mode power supply tutorial

This video explains the purpose of feedback resistors in a buck converter circuit and shows you how to calculate them. Then I show you how to build a high current adjustable power supply using an LM2678 and a potentiometer. Parts list: LM2678T-ADJ: Input electrolytic cap: Output electrolytic cap: Input and output ceramic […]

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Switch mode power supply buck converter

Switch mode power supply tutorial: DC-DC buck converters

Switch mode power supplies are a more efficient way to regulate voltage than linear regulators. In this video I explain buck converters, which are a type of switch mode power supply used to step down voltage. I also show you how to build a 5V 5A power supply using an LM2678. Parts list (Octopart) Schematic:

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Class D amplifier

Class D Amplifier Tutorial

There are many different types of amplifiers. The most commonly used in audio are class A, AB and D. Class D amplifiers are inherently efficient reaching efficiencies >90%. This video shows you how class D amplifiers work, and how to build your own 2x15W stereo amplifier on a breadboard. Class D amp kit mentioned in […]

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H bridge

H Bridge Motor Speed Controller Tutorial

An H bridge is a type of circuit that you can use to control the direction of electric motors. In this video I show you how an H bridge works and show you how to build one that can control the speed and direction of a brushed DC motor using PWM. Parts list: NE555 timer: […]

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PFET reverse voltage polarity protection

How to protect circuits from reversed voltage polarity!

This video shows different ways you can protect your circuit from backwards power connections. Diodes, schottky diodes and P channel MOSFETs are discussed.

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Transistor / MOSFET

Transistor / MOSFET tutorial

How to use an N channel MOSFET to turn anything on and off. Also, remember to put a 100k resistor between gate and ground if you want your FET to stay off by default!

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Basic electricity amps

Basic Electricity – What is an amp?

The first part in a series of videos about the basics of electricity.

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How to Turn an Old UPS into an Alkaline Battery Charger!

I recently lost my collection of electronic components, and was looking for a cheap source of parts I could use in my projects. It turns out that my old, broken uninterruptible power supply was a goldmine of useful components! Check out the video to see what I found inside. It turns out that I had […]

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robotic cat toy

Robotic cat toy

I made a robotic cat toy to keep my cat out of trouble. The project was built around the Axon microcontroller board and most of the effort was all in the software. The source code and project files are here, intended to be compiled with AVR Studio, AVR GCC and AVRlib. For more info about […]

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Fun with ultracapacitors!

So I recently got hold of some 2600F (no that is not a typo) ultracapacitors with an insanely low ESR of 0.7 milliohms, meaning they can discharge hundreds of amps even at low voltages. This video shows you some of the mayhem I got up to, and teaches some important capacitor formulas along the way. […]

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It's not the volts it's the amps

“It’s not the volts that kill you, it’s the amps!”

Afroman debunks the popular myth that it’s not the volts that kill you, it’s the amps. Basically, the volts directly determine the current flowing through your body, so the phrase is stupid and dangerously misleading.

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