The most surprising part of this build is how much range comes out of one chip and one knob. With the 0.1 uF ceramic in place, the circuit gives a high-pitched tone that shifts as the 10k potentiometer turns. Swap in the 10 uF electrolytic and you get a lower buzz, while the 100 uF one turns the output into rhythmic clicks whose speed can be adjusted. Three capacitors, three totally different sounds, from a single oscillator stage.
The circuit itself is a simple audio oscillator built on the CD40106 hex Schmitt-trigger inverter, powered by a 9V battery with a clip connector. PhilStudio puts the IC in a 14-pin DIP socket on a prototype perfboard, with two 7-pin screw terminal blocks carrying the connections, a power-indicator LED with its current-limiting resistor, and a 1/8-inch audio jack. Output goes to an LM386 amplifier board with a small speaker for testing.
The assembly method stands out to me. Every hookup wire gets a crimped ferrule before being soldered to the capacitors, potentiometer, and jack, then everything wires into the terminal blocks step by step. Before any soldering, a whiteboard session diagrams the IC pinout, with pin 14 to V+ and pin 7 to ground, and explains how a capacitor to ground plus a feedback potentiometer oscillates through charging and discharging cycles. A schematic and a frequency equation come with the parts list, and the CD40106 datasheet is linked too.
One open thread: the host says the circuit will be expanded in a future video, so this looks like a starting point rather than a finished instrument. That seems like the right place to leave it.
Project by PhilStudio. Watch it on their YouTube channel: