1 OPAMP UA741 2 Resistor 1MΩ 1 Resistor 2k2 1 NPN Transistor 2N2222A 1 47n Capacitor ------------------------------ C1 Ceramic Capacitor capacitance 10nF; J1 Piezo Speaker; R1 Rotary Potentiometer resistance 10kΩ; R2 Resistor resistance 100Ω; R3 Resistor resistance 470Ω; R4 Resistor resistance