In English, "a" (or "an") is a more general article, while "the" implies that there are specific instances of the concept that are relevant. There are two parts of these sentences that we can look at:
In the first part, the use of "a" vs. no article+the plural can suggest slightly different things:
(1) A strict constraint on the power consumption [...]
(3) Strict constraints on the power consumption [...]
Sentence 1 can be interpreted to mean "any strict constraint on power consumption would cause effect x". I think most people reading sentence 3 would also interpret it the same way as 1, but since you used the plural constraints, it could also be interpreted to mean "multiple [concurrent] strict constraints on power consumption would cause x." As another example, consider the following sentences:
(Ex. 1) Taking a painkiller can result in liver toxicity.
(Ex. 2) Taking painkillers can result in liver toxicity.
Example one suggests that any painkiller can cause liver damage, while example two could be interpreted as taking multiple painkillers at the same time can cause liver damage (which, in turn, can suggest that just taking one is safe, which may or may not be the meaning you want to convey). I think most English speakers would understand what you meant in either of the cases you presented, but if we're being pedantic, sentence 1 has slightly less room for ambiguity.
In the second part of the sentence, the use of no article/a(n)/the does slightly change the meaning:
(1) [...] severely affect the performance of electronic devices.
(2) [...] severely affect performance of the electronic devices.
(3) [...] severely affect performance of an electronic device.
In sentence 1, the most common interpretation is most likely that "x can affect (general) electronic devices" (both "one electronic device" and "multiple electronic devices" are possible interpretations, and both are reasonable here). Sentence 3 is more or less the same as sentence one. Sentence 2, however, is different. It implies that there is a set of electronic devices your sentence applies to, for example toasters and refrigerators but not ovens. Your audience would need to understand which devices "the" is specifying, typically clear from the context of the rest of the paragraph/article/etc.
In summary: "a" is the article to use when you don't have a specific object or type of objects in mind. "The" is what you should use when you're referring to a defined instance or set of objects.