How’s the temperature today? Cold, good or hot? Ambient temperature can be easily measured without any special temperature sensor. You just need… a common diode! Well, actually, a diode and a resistor. Diodes change their forward voltage drop at a rate of approximately -2.3 mV per degree Celsius (ºC), so we just need to measure that voltage.
You may want to start by reading Setting up a LED bargraph. Check also our other Free Articles.
I’ll be writing a few articles on easy and fun things you can do with a linear LED bargraph such as our Linear bargraph LED scale module, and this 1st one is meant to show you how to make the basic adjustments. Keep on reading and stay tunned!
Spanish version of our article Fun and easy to build buzzer circuit!
Me encontré con este circuito cuando tenía alrededor de 14 años y he jugado con él durante años. Este fue probablemente el circuito que más me fascinó en mis primeros años y que despertó en mí la pasión por la electrónica. Lo vi por primera vez en las revistas de electrónica brasileña, algunos de ellos ainda hoy en la prensa, pero un seguimiento de su origen a un circuito de un libro escrito en 1960 por Lou Garner - Transistor Circuit.
Este circuito es un oscilador, y es capaz de generar una onda de sonido, un tono. La frecuencia del tono (si es un sonido mas agudo o grave) es controlado por la resistencia variable. La potencia del sonido de este circuito es considerable, no ponga su oído demasiado cerca del altavoz de la primera vez 
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Me and this circuit met when I was around 14 years old and I played with it for years. This was probably the circuit that most fascinated me in my early years and that awoke in me the passion for electronics. I saw it for the first time in Brazilian electronics magazines, some of them still in print today, but I tracked its origins it to a circuit from a book written in 1960 by Lou Garner - Transistor Circuits.
This circuit is an oscillator, and is able to generate a sound wave, a tone. The tone’s frequency (if it’s a high or low sound) is controlled by the variable resistor. The sound volume of this circuit is considerable so, don’t put your ear too close to the speaker the first run .
Still have a PC with a parallel port laying around? In this AVR tutorial I will describe how to setup a minimalist system to develop AVR programs, using the C programming language, under Windows. This comprises of a really cheap hardware programmer, a test circuit and PC software. You will end following this tutorial with an AVR programmed by you blinking a LED on your bench . I’ll not explain in detail what all commands do; this tutorial focuses on setting up the development environment, leaving the applications development for another tutorial.
Portuguese speakers: Podem ver uma versão portuguesa deste artigo aqui.
