Funk (Twang) Guitar Effect Box Circuit

 

This is an audio effect circuit that give extra oscillation to your guitar, percussive, or semi percussive instruments, you can call it a funk box. This guitar effect circuit is basically a damped oscillator that is set slightly below its critical oscillation point. This is the figure of the schematic circuit;

Simple Digital Theremin Circuit

 

Here’s the Theremin circuit shown that uses digital component, so we can call it a digital Theremin. This circuit employs logic inverter 74C04 or CD4069 hex inverter and CD4046 phase-locked-loop (PLL) IC. The CD4069 logic inverter is operated as a fixed-frequency oscillator with frequency around 100kHz. The CD4046 is operated as a variable frequency oscillator which is adjustable around 100kHz. The exact center frequency of the on-chip oscillator is determined by R4, C2 and R3.