Transient suppression diode products have a single - way distinction, but whether the two-way TVS tube can be used to replace one-way? Single - way diodes are more suitable for the protection of what line?
From the market to see the two-way TVS tube application range more widely, from the product price point of view there is no difference, the key parameters of the capacitor C, the lower the better, which led to the electronic market and small factories generally use two-way TVS tube.
But through analysis above, unidirectional and bidirectional has many different, many places can be used for two-way two-way, but the specific use which is the most important at the circuit design of the project, some only one-way TVS.
First, how to distinguish between the TVS tube is one-way or two-way?
1 see model. Single from the model surface we can judge, although different brands named different, but there are rules:
Figure 1 two-way two-way pilot Fig. two unidirectional conduction2 with the use of a million
Measuring diode stalls, one-way, two-way 2 sides have voltage;
Measurement of DC, bidirectional symmetry, one-way only reverse avalanche breakdown characteristics, the general 1mA under test.
3 all TVS tube amplifier will have a cathode line, it is used to distinguish between positive and negative poles of the diode, and is not independent of the single.
Two, single / double use on the different points
1 unidirectional used in dc. Two-way communication;
2 TVS pipe has one way and two way, the characteristic of one-way TVS tube is similar to the voltage stabilizing diode, and the characteristic of the bidirectional TVS tube.
The equivalent of two diode reverse series;
3 pole capacitance Cj one-way than two-way large, in order to LRC, for example, one-way capacitor 65PF has C, two-way only 15PF;
4 USB data online all the way;
5 different current curve. The circuit symbol of the single direction TVS tube is the same as that of the common voltage regulator.
The characteristic curve as shown in Figure 3, the characteristics are the same with ordinary diode reverse characteristics for a typical avalanche PN junction devices.
Forward and reverse bidirectional diode are typical avalanche PN junction devices.
Specific selection or need professional engineers to guide, after the parameter field analysis for the selection of relatively safe.