0 Simple Hearing Aid

Hearing aid circuit powered by 1.5V battery. The circuit is a simple audio amplifier that pick up sounds then amplifies it to the headphone (Spk).

Part List :
R1 - 3.3 kilo ohms 1/4W
R2 - 120 kilo ohms 1/4W
R3 - 180 kilo ohms 1/4W
R4 - 10 kilo ohms 1/4W
R5 - 4.7 ohms 1/4W
Q1, Q2 - 2N2222 or similar NPN transistor
Q3 - 2N3906 or similar PNP transistor
C1 - 2.2uF electrolytic capacitor
C2 - 4.7uF electrolytic capacitor
Mic - electret microphone
Spk - headphone 8ohms up to 32 ohms
Bat - 1.5V battery

2N3906 pins

2N2222 pins