Electronic Circuits and Diagram-Electronics Projects and Design

Description.

Just about any power transistor can be used in  this megaphone.Its suitable for boats,playing fields etc.the transistors Q1  & Q2 are the HEP-230 type which are easily available in the market.The transistors are parallely connected to handle the required power and speaker matching.The microphone is a carbon type like that used in telephone hand sets.If  a regular carbon mike is used the push-to-talk (PTT) switch can be connected in place of S1 to provide PTT operation.There will be no warm up or “capacitor charge time.

Circuit diagram with Parts list.

Notes. 

• The circuit can be powered from a 12V battery or 12V DC power supply.
•  The POT R1 can be adjusted to obtain maximum volume with minimum distortion.
• It will be always better to mount the transistors on heat sink.