SCR_TRIAC

INTRODUCTION

Approvals in their outer aspect, SCR and TRIAC are resembled like many water drops. To distinguish them, therefore, is impossible, if it is not rerun to the exact acknowledgment of the acronym and to the ritrovamento of this on a common prontuario. But the acronyms, today attributed to these semiconductors, are many, too many for being collections all in a handbook modernized to the capacity of the amateurs. Which, often, during their activity, are found in embarrassment, because, ignoring the characteristic electrical workers, they cannot lead those tests that serve to identify the components and to know their state of efficiency. Here because the idea is risen us to conceive a simple circuit, of immediate realization, absolutely economic, to entrust our hobbyist readers, with which they can distinguish, with a sure rapidity, a SCR from a TRIAC, estimating some, at the same time, the behavior electrical worker, is worth to say the validity works them. But since the principle of operation of the device is based on the use, from part of the SCR, of average cycle of the alternated voltage, while the TRIAC works with the entire cycle of the same voltage, alla presentation of the apparatus must make to precede those theoretical slight knowledge that regulates the way to behave itself of these particular diode , that by now all know and whose employment is often from we prescribed for the construction of the many plans that, month for month, come publishes to you on this periodical.

Known also under the name of controlled diode , the SCR inner is composed from three P-N splices, that they form a semiconductor of P-N-P-N type, similar to two normal diode  connects to you in series. They finishes relative to the anode makes head more external the P semiconductor, while the cathode remains connected with the N semiconductor situated in the opposite part. A1 according to field of P material is connected the representative electrode of the gate ones, said also "door". The symbol electrical worker, that it characterizes diode  SCR, is that one represented in figure 1, while the outer aspect more common than this semiconductor it can be identified with one of the graphical expressions brought back in figure 2.

DIODE