2N684A

Thyristors - SCRs

A Silicon Controlled Rectifier, abbreviated as SCR, is a member of the thyristor family. It is a solid-state semiconductor device that functions in a way similar to a rectifier diode. Also known as a thyristor, it has four layers of alternating P-type and N-type semiconductor material and it is used to control non-stop current flow in an alternating current circuit, with either one or three terminals. The 2N684A SCR is a device with higher peak non-repetitive and repetitive surge current capability compared to other similarly rated SCRs, and a greater ambient operation temperature rating.

2N684A Application Field and Working Principle

The 2N684A application field is primarily in industrial and commercial applications.

The main uses of the 2N684A SCR products within these industries are motor control and light control, such as for electric drill, vacuum cleaner, and water heater. For example, it is used to control the speed of electric drills, to control the fan speed on air conditioners, and to limit the current in the heater elements of water heaters or electric kettles.

The working principle itself is fairly simple. The SCR uses junction gate physics to operate, and its main parts are the anode, cathode, and gate terminals. When a proper gate current is applied, excess majority carriers (holes or electrons) will be injected into the N-type region and by recombining, they will establish a potential barrier between the two P-N junctions. Thus, it will be necessary to maintain a sufficient gate current flow in order to keep the SCR in its conducting state. When the gate signal is removed, the majority carriers will be swept away; the potential barrier between the two P-N junctions is then restored, thereby deactivating the device.

The 2N684A SCR also has a variety of other features. It has a breakdown voltage of 60 volts and an average on-state current of 1.3A. When a high reverse voltage is applied across the anode and cathode terminals, the 2N684A is able to retain a minimum leakage current of 200nA. It can also withstand a maximum dissipation of 5W and a maximum surge peak current of 30A.

In conclusion, the 2N684A SCR is a reliable and versatile device that is well suited to a variety of industrial and commercial applications. It has a variety of features, such as its breakdown voltage, leakage current, and surge peak current, that make it an ideal choice for many applications.