This module explores how a classic transistor flip-flop can be transformed into a voltage-controlled oscillator. No ICs — just analog logic sculpted into sound.
Core Circuit Elements
- 2 × NPN Transistors (e.g. 2N3904)
- 2 × Capacitors (10µF electrolytic)
- 4–6 × Resistors (fixed + voltage-controlled)
- 1 × Control Voltage Input (0–5V or 0–9V)
- Optional: RC filter for waveform shaping
How It Works
- Transistors toggle via capacitor-coupled feedback
- Capacitor charge time sets oscillation frequency
- Control voltage modulates resistance in RC path
- Output: square wave or filtered triangle-like wave
Circuit Variations
- JFET as voltage-controlled resistor
- LED indicators on transistor collectors
- RC filter for smoother waveform
Visual Index
Interactive diagram: voltage slider → waveform preview → frequency readout
Philosophical Footnote
From binary logic comes rhythm, and from rhythm comes tone. Even the simplest components — when arranged with care — can sing.