2N688A

The 2N688A Silicon Controlled Rectifier (SCR) is a thyristor that has been widely used in power electronics for decades. In this article, we will look at the application field and working principle of this ubiquitous device.

Power Electronics is an area within the field of electrical engineering which focuses on efficient conversion and control of electrical power. As such, SCR\'s are used in the design of circuits that make these conversions or control the power or current. A common application for 2N688A SCR\'s is in the control of current or voltage in switching power supplies. This allows for the precise selection of output voltage or current, and prevents over-voltage or over-currents. Other applications include motor control, temperature control, and voltage clamping.

The 2N688A is a four-layer, low-cost, high-power silicon-controlled rectifier. It is composed of a P-N-P-N structure and utilizes two PN junctions and two metal contact terminals. The metal contacts, which are located at the anode and cathode terminals, allow current to flow into and out of the device when the circuit is turned on.

The basic functioning of an SCR is described in terms of its three terminals, the anode, cathode, and gate. The anode and cathode are the two primary regions of the SCR that conduct current. Current will only flow between them when the circuit is on. The gate terminal controls the current flow between the anode and cathode. When the gate terminal is energized, a small current flows from the gate to the anode, which in turn activates the SCR, allowing current to flow between the anode and cathode.

The 2N688A SCR is a bidirectional device, which means it can conduct current in either direction when triggered. Moreover, it is a latching device, meaning it will remain latched in the on state even after the gate voltage is removed. To turn the SCR off, the current between the anode and cathode must be interrupted. SCR\'s are often used in AC circuits because of their latching behavior, which reduces the need for continuously energizing the SCR.

The 2N688A SCR is a widely used electronic device in power electronic applications. Its application field and working principle have been discussed above. This article has highlighted the basics of SCR construction and operation, discussing the anode, cathode, and gate terminals, and the behavior of an SCR in AC or DC circuits. With its latching and bidirectional properties, the 2N688A SCR is well-suited for use in many practical applications.