Any asynchronous DC/DC converter requires a so-called freewheeling diode. In order to optimize the overall efficiency of the solution, it is usually preferred to choose Schottky diodes with low forward voltage. Many designs use diodes recommended by a converter design (network) tool.
The reverse saturation current Icbo between the collector and base, when the emitter is open (Ie=0) and a specified reverse voltage Vcb is applied between the base and collector, is only related to temperature and remains constant at a certain temperature. Therefore, it is called the reverse saturation current between the collector and base.
A bipolar junction transistor is equivalent to two back-to-back diode PN junctions. The forward biased EB junction injects holes from the emitter into the base region, most of which can reach the boundary of the collector junction and reach the collector region under the action of the reverse biased CB junction potential barrier electric field, forming a collector current IC.
Single junction transistor (UJT), also known as base diode, is a semiconductor device with only one PN junction and two resistive contact electrodes. Its substrate is a strip-shaped high resistance N-type silicon wafer, and two base electrodes b1 and b2 are respectively led out by ohmic contacts at both ends.
In engineering technology, the internal structure of surface mount diodes is basically the same as that of ordinary diodes, both consisting of a PN junction. Therefore, the detection method of surface mount diodes is basically the same as that of ordinary diodes. The detection of surface mount diodes is usually measured using the R × 100 Ω or R × 1 k Ω range of a multimeter.
TVS devices can be divided into two types based on polarity: unipolar and bipolar; It can be divided into universal and specialized types according to its purpose; According to packaging and internal structure, it can be divided into axial lead diodes, dual in-line TVS arrays, surface mount and high-power modules, etc. The peak power of axial lead products can reach 400W, 500W, 600W, 1500W, and 5000W.
