MK484
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 run from a single 1.5-volt cell
.
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.
Integrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...
is a fully functional AM radio detector on a chip. It is constructed in a TO-92 case, resembling a small signal transistor
Transistor
A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current...
. It replaces the similar ZN414
ZN414
The ZN414 was a low cost, single-chip AM radio integrated circuit. Launched in 1972, the part was designed and supplied by Ferranti, but was also available from GEC-Plessey...
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 run from a single 1.5-volt cell
Electrochemical cell
An electrochemical cell is a device capable of either deriving electrical energy from chemical reactions, or facilitating chemical reactions through the introduction of electrical energy. A common example of an electrochemical cell is a standard 1.5-volt "battery"...
.
Standard operation
The simplest circuit employing the MK484 can be constructed using a battery, earphone (or high-impedance speaker), tuning condenser.Extended operation
The output of the MK484 can be fed into the base of a transistorTransistor
A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current...
to provide greater amplification as a class A amplifier, however this is often an inefficient design. Conversely, the LM386
LM386
The LM386 is an integrated circuit consisting of a low voltage audio power amplifier. It is suitable for battery-powered devices such as radios, guitar amplifiers, and hobbyist projects...
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
1N4148
The 1N4148 is a standard silicon switching diode. Its name follows the JEDEC nomenclature. The 1N4148 has a DO-35 glass package and is very useful at high frequencies with a reverse recovery time of no more than 4ns. It was second sourced by many manufacturers; Texas Instruments listed their...
) are recommended to create a voltage drop
Voltage drop
Voltage drop is the reduction in voltage in the passive elements of an electrical circuit. Voltage drops across conductors, contacts, connectors and source internal resistances are undesired as they reduce the supplied voltage while voltage drops across loads and other electrical and electronic...
, as to avoid overvoltaging the MK484.
Advantages
- Compact size
- Low power consumption
- Low cost: Rs 40 to 60 in Indian electronic markets
- Retails from 65 cents each on various websites