This circuit will amplify a signal by a factor 4. It can easily be powered by a 9V battery. No circuit board needed if assembled as follows :
PARTS LIST:
Unless otherwise stated, resistor wattage = 0.25W.
- R1 = 22KΩ
- R2 = 100KΩ
- R3 = 10KΩ
- C1 = 10µF/10V
- T1 = BC549
or BC149