Analog Electronics Projects

Analog electronics often have higher power requirements than digital electronics.

In analog electronics you use a continuous signal rather than the ones and zeroes of digital electronics. Analog electronics projects can range from simple calculators and function generators to radios, musical instruments and more. Different analog electronics projects require different skill levels. Whether you're an electrical engineer, an experienced tinkerer, or just starting out, analog electronics can make for some interesting projects.

Portable Headphone Amplifier

Most portable music devices have weak built-in headphone amplifiers that can't match the power requirements of quality headphones. A headphone amplifier will not only boost the signal level but will also improve the sound quality. You can make a simple headphone amplifier that fits in a cigar box. It's based around an operational amplifier, or op-amp, a common amplifier IC in analog electronics. Op-amps have an incredible variety of uses, including power amplification, wave generation, and performing mathematical operations like multiplication, differentiation and integration. This circuit runs off of a pair of 9-volt batteries, and is easily constructed using a soldering iron and a handful of inexpensive components.

Square Wave Generator

If you want to make sound, not just listen to it, try building a square wave generator. This is another straightforward op-amp based circuit, and it's a good starting point from which to move on to more complicated projects. A square wave is a wave which flips back and forth between the positive and negative supply voltage. The waveform is rectangular and clipped, as opposed to the smooth curves of a sine wave. This circuit can be built using only a few components that cost pennies. Listen to the wave by connecting a speaker to the output line, or monitor it on an oscilloscope. Adjust the frequency by experimenting with different values for components in the circuit.

Theremin

Invented in 1919 by Leon Theremin, the theremin was the first electronic musical instrument. The spooky, ethereal sounds it produces became a staple of early science fiction film soundtracks. You don't touch a theremin to play it. Rather, you play a theremin by moving your hands around a pair of antennas, manipulating the capacitance between the antennas and your hands. Building a traditional analog theremin is a challenging but rewarding project, recommended for those with some experience in electronics. You'll need a lot of components, and the circuit must be built with precision in order to function properly. Because a theremin uses tiny variations in capacitance, the PCB needs to be laid out very carefully to avoid unintended interference.

Guitar Effects

Another challenging but fun project that will impress your friends is a guitar effects pedal. Analog effects have a different character than digital effects, and are becoming harder to find in stores. These circuits are usually less complex than the theremin, but require a lot of components so some prior electronics experience is recommended. Use a solid enclosure that can withstand being stepped on.

References

• DIY Audio Projects: CMOY/Grado Headphone Amp
• Hyperphysics: Square Wave Generator
• Theremin World: What's a Theremin?
• Theremin World: Schematics
• DIY Stomp Boxes: Selected Schematics