In previous article about how to make a radio we have discussed a simple crystal radio receiver circuit. The schematic mentioned here is also a simple AM radio circuit but it is not using a crystal, it is using high gain preamplifier stage of transistor BC 549. The circuit is using only few
components to make a good quality am receiver. For making 200uH coil take a #26 enameled copper wire and wound 60 turns on a 1cm diameter and 7.6cm long ferrite rod. The circuit can be powered with a 9 volt battery.