1N4747A

A 1N4747A diode is a type of Zener diode that is used as a low current noise-limiting device. It is commonly found in electronic circuits, particularly in audio and medical equipment, as it is ideal for high value, low infrared sensitivity, high voltage applications. The diode is a quarter watt diode having a high voltage rating of 39V, and a low current rating of 50mA.

Application Field

1N4747A diodes are used to help prevent interference from cords or other power sources. When placed in a circuit, the diode helps to limit and eliminate intermittent or noise signals from entering the circuit due to inappropriate voltage sources or other external conditions. Other applications for 1N4747A diodes include protecting various audio components and preventing distortion due to over voltage from batteries or other power sources.

Working Principle

The working principle of the 1N4747A is based on the Zener effect. This effect is created when a diode is subjected to an electric field greater than its peak reverse voltage rating. When this happens, the diode starts to break down, allowing electrons to flow more freely across the junction. This increased electron flow produces a voltage drop across the junction, which helps protect the rest of the circuit from voltage spikes or other noise signals.

The breakdown voltage is determined by the characteristics of the semiconductor material used in the diode. In the case of the 1N4747A, the breakdown voltage is 39V. The diode will not begin to break down until the electric field across the junction exceeds this value, and will remain in the off (or open) state until then.

Once the breakdown voltage is exceeded, the 1N4747A will allow current to flow from the anode to the cathode. This process is known as “Zener regulation” because it allows the diode to regulate the amount of current that can pass through the circuit and help prevent excess voltage from damaging the components.

In addition to Zener regulation, the 1N4747A can be used in reverse bias protection circuits. When a negative voltage is applied to the diode, the breakdown voltage will be reduced, causing it to break down at a lower voltage and help protect the circuit from over voltage conditions.

The 1N4747A is a versatile device and with its low current and high voltage ratings, it makes an ideal choice for a variety of circuit protection applications. Its ability to help limit noise and prevent distortion make it a popular choice for audio and medical equipment, as well as other electronic circuits. It is a reliable and cost-effective way to ensure your circuits are protected.