MK484
From Wikipedia, the free encyclopedia
The MK484 AM Radio IC is a fully-functional AM radio detector on a chip. It is constructed in a TO-92 case, resembling a small signal transistor. It replaces the similar ZN414 AM radio IC from the 1970s. The MK484 is favored by many hobbyists. It is advantageous in that it performs well with minimal discrete components, and can be run off of a single 1.5-volt cell.
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[edit] Standard operation
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The simplest circuit employing the MK484 can be constructed using a battery, earphone (or high-impedance speaker), tuning condenser, and antenna.
[edit] Extended operation
The output of the MK484 can be fed into the base of a transistor to provide greater amplification as a class A amplifier, however this is often an inefficient design. Conversely, the LM386 audio amplifier may be used to drive a small speaker.
Note that higher voltage is required if the LM386 is to be used. Therefore, small signal diodes (such as 1N914 or 1N4148) are recommended to create a voltage drop, as to avoid overvoltaging the MK484.
[edit] Advantages
- Compact size
- Low power consumption
- Low cost: Retails from 65 cents each on various websites
