This jet engine sound generator circuit is based on the sound generator IC HT2844P from Holtek Semiconductors. This particular IC can make four sounds namely low speed sound of jet engine, high speed sound of jet engine, missile sound and machine gun sound. Each of these sounds can be activated by connecting the pins 12, 13, 14and 15 to ground by using the respective push button switches. Resistor R3 can be used for manually increasing or decreasing the speed. LED D1 gives a visible indication of the sound.
IC1 = HT2844P
R1 = 220R, R2 = 470R
VR3 = 220K, R4 = 330K
C1 = 1uf 16v
Q1 = BC108
K1 = Piezo Buzzer
B1 = Battery 3volt.
The circuit can be powered from a 3V battery.
Do not give more than 3.3V to the IC.
K1 can be a 200mW/8 Ohm speaker.
IC1 must be mounted on a holder.