how can i increase and rise the voice in my circuit ?
My project called " Four Tone Siren "
this is the circuit for my project .... I really need to increase the voice
because it's very small you can't hear it except if you put the circuit close to you
and i only hear 3 tone and my project is 4 tone.
can you tell me please what is the reason ?
my final project after 2 days please :(
this is my parts :
Resistance = 220 Ohms
Battery Container 3V