About The Circuit
Here isthe circuit diagram of a simple power megaphone circuit. All you have to look out for is whether you get the perfect power and speaker matching. For that the transistors Q1 and Q2 (HEP 230) are connected in parallel. An input voltage supply of 12 Volts is required. It can be either given from a battery supply or a DC power supply. A carbon type michrophone is more than enough for the circuit to work. It is the same component that is used in our ordinary telephone sets. A Push-to-talk (PTT) switch can be easily setup if we use an ordinary carbon type michrophone.
Any type of power transisitors can be used for this circuit. You have to only look out that the transistors used are kept on heat sinks. The volume control can be adjusted wiith the help of the POT R1, through which you will get max. volume with min. distortion. Take a look at the circuit diagram given below.