1. THE THEREMIN Marco A. Rodriguez Department of Physics & Astronomy, College of Charleston, Charleston, SC

2. WAVES / SOUND

3. Resistor-RCapacitor-CInductor-L555 IC

4. PARALLEL-PLATE CAPACITOR MODEL

5. LÉON THEREMIN Born 1896 Russian research 1920 The high frequency oscillator

6. OPERATION: HETERODYNING High to Low frequency conversion Non-linear signal processing device Heterodynes Filtering to audible frequency range

7. OPERATION: HETERODYNING

8. OPERATION: THE VARIABLE OSCILLATOR LC circuit-based Capacitor: Antenna + Hand

9. OPERATION: THE FIXED OSCILLATOR Initially tuned at high frequency Change in capacitance = change in voltage Voltage-controlled amplifier

12. CHALLENGES Complexity/construction of circuit Frequency mixing Cost of materials

13. OPTICAL THEREMIN Varying resistance vs. capacitance No need for RF oscillators No need for heterodyning

14. THE 555 TIMER Astable mode Light-dependent resistance

17. CHALLENGES IC sensitivity Soldering work (12 hours of my life I will never get back) Resistor/Capacitor Tuning

18. Demonstration