Conjuction

A word used to connect clauses or sentences or to coordinate words in the same clause. e.g. but, and, yet, or, because, nor, although, since, unless, while, where, etc.

A coordinating conjunction is a word that joins two elements of equal grammatical rank and syntactic importance. They can join two verbs, two nouns, two adjectives, two phrases, or two independent clauses

There are seven Coordinating Conjunctions:-

• For - Explains reason or purpose (just like "because")

• And - Adds one thing to another

• Nor - Used to present an alternative negative idea  to an already stated negative idea

• But - Shows contrast

• Or - Presents an alternative or a choice

• Yet - Introduces a contrasting idea that follows the preceding idea logically

• So - Indicates effect, result or consequence

A subordinating conjunction is a word or phrase that links a dependent clause to an independent clause. This word or phrase indicates that a clause has informative value to add to the sentence’s main idea, signaling a cause-and-effect relationship or a shift in time and place between the two clauses. 

• Because of him, I learned how to start my own business. 
• Everything will fall into place if you start at the beginning, 

Correlative conjunctions work in pairs to join words, phrases, or clauses. The correlative conjunctions are either...or, neither...nor, both...and, not only...but also, whether...or. 

• I want either a pink sofa or a purple one. 
• I'll study both English literature and art history. 
• I didn't know whether you'd want milk or cream, so I grabbed both. 

A conjunctive adverb, adverbial conjunction, or subordinating adverb is an adverb that connects two clauses by converting the clause it introduces into an adverbial modifier of the verb in the main clause. 

For example, in "I told him; thus, he knows" and "I told him. Thus he knows", "thus" is a conjunctive adverb.

Negative and Positive Senses -  

So As - Is always treated as in negative senses. 

As As - Can be treated in both +ve and -ve sense. 

Hardly, Scarcely, Barely are -ve in nature. 

Until and Unless are also -ve conjunctions but Until is Time-Oriented and Unless is action-oriented.

Although and though are contradictory conjunction, can't have both in the same sentence.

Doubt alone can't make -ve sentence.

But is also contradictory.