THE THEREMIN

Marco A. Rodriguez

Department of Physics & Astronomy, College of Charleston, Charleston, SC

WAVES / SOUND

Resistor-R Capacitor-C Inductor-L 555 IC

PARALLEL-PLATE CAPACITOR MODEL

LÉON THEREMIN

• Born 1896

• Russian research 1920

• The high frequency oscillator

OPERATION: HETERODYNING

• High to Low frequency conversion

• Non-linear signal processing device

• Heterodynes

• Filtering to audible frequency range

OPERATION: HETERODYNING

OPERATION: THE VARIABLE OSCILLATOR

• LC circuit-based

• Capacitor: Antenna + Hand

OPERATION: THE FIXED OSCILLATOR

• Initially tuned at high frequency

• Change in capacitance = change in voltage

• Voltage-controlled amplifier

CHALLENGES

• Complexity/construction of circuit

• Frequency mixing

• Cost of materials

OPTICAL THEREMIN

• Varying resistance vs. capacitance

• No need for RF oscillators

• No need for heterodyning

THE 555 TIMER

• Astable mode

• Light-dependent resistance

CHALLENGES

• IC sensitivity

• Soldering work

(12 hours of my life I will never get back)

• Resistor/Capacitor Tuning

Demonstration