Hearing aid machine with constant volume is a battery powered electronics device that makes listening easier for people with hearing loss, consist of microphone, amplifier and receiver.
RESISTORS, R1&R9
10K 1/4W
RESISTOR, R2
1M 1/4W
RESISTOR, R3
4K7 1/4W
RESISTORS, R4&R7
100K 1/4W
RESISTOR, R5
3K9 1/4W
RESISTOR, R6
1K5 1/4W
RESISTOR, R8
100R 1/4W
POTENTIOMETER
P1=22K
CAPACITORS,C1 &C2
100nF63VCER/POLY
CAPACITORS,C3 &C6
1uF 63VCER/POLY
CAPACITOR, C4
10uF 25V ELECTR
CAPACITOR, C5
470uF 25 ELECTR
TRANSISTORS,Q1,
Q2 & Q3
BC 547 45V 100mA
NPN
TRANSISTOR, Q4
BC 337 45V 800mA
NPN
MIC1
Miniature electric
microphone
SW1
SPST Switch
J1
Stereo 3mm Jack socket
B1
1.5V Battery
DIODE, D1
IN414875V150mA
CONCLUSION
The preliminary test of the circuit in proteus shows the circuit will operate after prototype building which will provide quality sound to hearing loss.