How to Build a Class-D Power Amp

The mighty Class-D amplifier—build one yourself and be amazed by its efficiency. The heat sink barely gets warm! Have you always wanted to build your own audio power amplifier? An electronic project where you not only see the results but also hear them? If your answer is yes, then you should continue reading this article on how to build your own Class D amplifier. I will explain to you how they work and the ...

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WELL-ENGINEERED RF AMPLIFIER POWERS HAM RADIO CONTACTS

Typically, amateur radio operators use the minimum power needed to accomplish a contact. That’s just part of being a good spectrum citizen, and well-earned bragging rights go to those who make transcontinental contacts on the power coming from a coin cell. But sometimes quantity has a quality all its own, and getting more power into the ether is what the contact requires. That’s where builds such as this we ...

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The top 10 crystal oscillators from SnapEDA

A crystal oscillator is an electronic circuit that generates an electrical signal with a very precise frequency. To achieve this, it uses the mechanical resonance of a vibrating crystal made of piezoelectric material. The first crystal oscillator was invented in the late 1920s by Walter Guyton Cady who was interested in submarine detection with ultrasonic waves. He suggested that a piezoelectric resonator c ...

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REVERSE ENGINEERING A TWO-WIRE INTERCOM

There was a time when an intercom was simply a pair of boxes with speakers joined by a couple of wires, with an audio amplifier somewhere in the mix. But intercoms have like everything else joined the digital age, so those two wires now carry a load of other functionality as digital signalling. [Aaron Christophel] installs these devices for a living, and has posted a fascinating reverse engineering vid ...

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Simple Audio Amplifier

In most cases first project in electronics for beginners is building simple audio amplifier. That is because it requires small number of elements and not a lot of knowledge to build one. For low power amplifiers we could use integrated circuits like TDA family. But I will show how to make amplifier using operational amplifier. This amplifier is only to proof the concept. It real use can be as preamp for gui ...

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VU Meter – LED Noise-o-Meter for Classrooms

I built this a short while ago as an idea to use in a primary classroom setting. Poster displays are often used by primary teachers wanting to control the noise levels in their classrooms but I wanted to add technology to make it dynamic and responsive. The motivation for this came after seeing the Adafruit Digital NeoPixel LED Strip online and realising its potential as part of a VU meter. Everything else ...

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10W STEREO AUDIO AMPLIFIER

This project is a 10W Stereo Audio Amplifier based on TDA1521 IC. DESCRIPTION The project built around Philips TDA1521 IC, The project provides high quality audio 2X10W Audio output. The device is especially designed for mains fed applications, (e.g. Stereo TV Sound and Stereo Radio). The circuit designed for asymmetrical power supply systems. SPECIFICATIONS It has few external components Input muted during ...

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MINI STEREO AUDIO AMPLIFIER

This project is a Mini Stereo Audio Amplifier based on TDA2822 IC. DESCRIPTION The dual low power amplifier built around TDA2822 8pin DIP. IC, it is mainly designed to use in portable players, radios and other building block project. A 3V supply can be used to drive headphones providing 20mW in 32 Ohms per channel, and a 12V power supply will provide 1W in 8 Ohm per channel for small loudspeakers. SPECIFICA ...

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3A THERMOELECTRIC COOLER (TEC) DRIVER

3A TEC Driver Module is a complete power stage solution to drive Thermoelectric Cooler (TEC). The required DC voltage input controls the output current. It consists of the Texas instruments DRV593 power driver IC, along with a few discrete passive components required for operation. It also includes jumpers for configuring the features of the device, LEDs for fault monitoring, and an output filter. The 4 Pin ...

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Current Sensor Amplifier & Over Current Switch

Current sensor amplifier and over current switch project is based on ACS714-30A current sensor and LM358 Op-amp, ½ of  LM358 op-amp used as an amplifier for low voltage  and 2nd 1/2 LM358 op-amp used as comparator which provides over current TTL output, trimmer potentiometer provided to set the over current limit.  ACS714 sensor measures the current up to +/-30Amps, final output of the amplifier is 235mV/1A ...

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Sensor board for micro:bit

Features 3V and GND connections can be made from either side and allow you to power a second board such as the MonkMakes Relay Board or MonkMakes Speaker. LED ‘power on’ indicator Reverse polarity protection All three sensors are analog and can be connected to pins P0, P1 and P2 using alligator clips. Getting Started Connecting to your micro:bit You only have to wire up the sensors that you are actually usi ...

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Making the Electronics for CDM324 – 24GHz Doppler Motion Sensor

The Doppler Effect I'm sure you're quite familiar with the Doppler effect: you send an RF signal at a given frequency to a target, and if this object/person is moving the reflected signal's frequency will be shifted. This is the reason why a fire truck's siren has a higher pitch when the truck is going towards you than when it is going away. The CDM324 / IPM165 Motion Sensor You may recall the article I wro ...

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