电路图

R1 = 1K - 1/4W Resistor
R2 = 100K - 1/4W Resistor (See Notes)
C1 = 2.2uF-50V Electrolytic Capacitor
C2 = 220µF - 25V Electrolytic Capacitor (See Notes)
D1 = 5 or 10mm. Ultra-bright red LED (See Notes)
D2 = 1N5819 - 40V 1A Schottky-barrier Diode (See Notes)
IC = 7555 or TS555CN CMos Timer IC
BZ = Piezo sounder (incorporating 3KHz oscillator)
B1 = 1.5V Battery (AAA or AA cell etc.)
Two small crocodile clips
Two pieces of stiff wire of suitable length
Battery socket, etc.