The transistors can be BC547 and BC557 for the NPN and the PNP respectively, while the diode can be 1N4148. The working efficiency may not be as good as a superhetrodyne, nevertheless is just enough for a good reception of all local stations. This helps just one transistor to do the job of two transistors which results in a much higher gain from the design. The first transistor is configured to work in the reflex mode. The MW receiver works with four transistors. Once built it can be expected to work immediately without any hassles. Use the Following type of GANG Condenser for the Trimmer (use the center pin and any one of the output pins from the MW side) Simple High Performance MW Receiver CircuitĪn Improved version of the above Medium Wave radio can be studied in the following paragraphs. Parts List for a simple 2 transistor radio receiver with speaker T1's emitter has been configured as a feedback link to the input stage, this inclusion greatly enhances the performance of the radio making it extra efficient while identifying and amplifying the received signals. T2 effectively amplifies the signals so that it becomes audible over the connected speaker loud and clear. The final stage employs the transistor T2 which operates as a simple audio amplifier, the demodulated signal is fed to the base of T2 for further amplification. T1 extracts the audio from the received signals and amplifies it to some extent so that it may be fed to the next stage. The next stage which comprises T1 functions as a high frequency amplifier as well as a demodulator. The trimmer sets and tunes the frequency which needs to be passed across to the next stage. The antenna coil collects the MW signals present in the air. As can be seen in the given circuit diagram, the design is as simple as it can be, just a couple of general purpose transistors and a few other passive components for configuring what looks like a nice little AM radio receiver unit.
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