Complete Radio Set with MK484 and Loudspeaker
Description:
A complete AM radio set based on the MK484 IC (formerly ZN414). It uses a PNP transistor and can drive a 150R loudspeaker.
Notes:
Chad has built a complete radio receiver using 1 IC and a single transistor. The IC requires around 1.2 to 1.6V and this is supplied via the 3V battery in series with 2 diodes 1N4114 diodes, (1N4004 can be substituted) and the 2k volume control.
Coil Details:
The Loopstick Coil is 2 7/8" in length and 6/16" in diameter. Tickler Coil is 6 turns -- and is spaced about one inch from primary coil. Primary coil is wound with 28 gauge enameled wire and the feedback coil is plastic insulated -- similar gauge . I do not know the permeability of the ferrite rod, I would guess it is 50 or so, for this is a ferramic and not powdered iron . The small 18pf ceramic condenser that provides the feedback can be as high as 22pF or even 33pF . .
Images:
Chads finished receiver can be seen below.
The audio output is amplified by a single 2N404 PNP germanium transistor and can directly drive a 150 ohm loudspeaker. The loudspeaker was purchased from "American Science and Surplus".