"This code practice oscillator kit has plenty of audio with a clean crisp tone. If deciding to build this as a kit, you need to be able to read a schematic and be able to do fine soldering. I bought the kit and have been an electronic kit builder for decades. I put the kit together in less than an hour. It worked perfectly once I soldered in all the components and connected a 9volt battery, speaker, and key. There are not a lot of in expensive choices for a practice code oscillator. I would highly recommend this one!"
Code Practice Oscillator Kit