Electronics-Lab.com Blog

ermicro.com writes:

Most of microcontrollers work within 5 volt environment and the I/O port can only handle current up to 20mA; therefore if we want to attach the microcontroller’s I/O port to different voltage level circuit or to drive devices with more than 20mA; we need to use the interface circuit. One of the popular method is to use the Bipolar Junction Transistor (BJT) or we just called it transistor in this tutorial. I have to make clear on this BJT type to differentiate among the other types of transistors family such as FET (Field Effect Transistor), MOSFET (Metal Oxide Semiconductor FET), VMOS (Vertical MOSFET) and UJT (Uni-Junction Transistor).

Using Transistor as a Switch – [Link]

bkraz333 writes: [via]

I describe how to design a simple transistor circuit that will allow microcontrollers or other small signal sources to control low-power actuators such as solenoid valves, motors, etc.

How to design a transistor switching circuit – [Link]

Jon Chandler explorers the often overlooked calculations behind selecting the right resistor for an LED. This somewhat simple task is taken for granted by many, although it’s a world of mystery for others.

Got an LED and have no idea what resistor to use with it? Jon covers it step by step.

LED Calculations – [Link]

Oscilloscopes are surprisingly easy to use once you’re familiar with a few basic controls. They’re extremely useful for testing and can provide newcomers with a whole new way to view the world of electronics & electricity – plus they look impressively cool/awesome while in use!

The Oscilloscope – [Link]

If you need to interface a higher voltage sensor output with a lower voltage chip the simplest solution is the good old fashioned voltage divider. Here’s an online calculator to help you compute the necessary resistance values courtesy of Raltron.com. [via]

Voltage divider calculator – [Link]

The operational amplifier is one of the most useful analog ICs available, and one of the most daunting for beginners and experienced engineers. Above is a diagram of an op-amp in a closed loop non inverting configuration. Probably the most used configuration. [via]

Operational Amplifier howtos – [Link]

For the absolute beginner it may be hard to understand what Voltage, Current, and Resistance are.Think of voltage as water pressure, current as the size of the pipe, and resistance as a valve or restriction in the pipe.

What is Voltage Current and Resistance – [Link]

A Resistor “resists” current flow. Think of it as a restriction in a water pipe only for electricity.

What is a Resistor? - [Link]

Testing a Diode is easy but much easier with an analog multi-meter.

How to Test a Diode? – [Link]

A capacitor blocks DC current but allows AC current by essentially charging up like a tiny battery, once charged the capacitor stops allowing current flow until the flow reverses.

What is a Capacitor and How to Test One – [Link]