With what verbal form can とたん be used？

Question

I studied that とたん must be used after a verb in the past form, and that, also the clause that follows it is in the past form. In this case it bears the meaning of "as soon as something happens, something else also happens". However, I saw that とたん can also be preceded by a present tense and that the following clause can be present too, but I'm not sure if the meaning of とたん then changes. As in:「会社に入る途端に勉強しなくなる人が多い」. Could somebody provide me some examples to figure it out?

Answer 1

「途端」と言う意味は、ある物事が起きた後そのすぐになにかのアクションが起きるときに使います。
英語だと、immediatelyやas soon asと同じ様な意味です。
(The meaning of the word "途端" is used when an action occurs immediately after something happens.)

今回の場合ですと、(In this case,)

社会に入る途端勉強しなくなる

と言うのは、「社会に出たらすぐに勉強しなくなる」、または「社会に入った瞬間に勉強と言う物をしなくなる」と言うことを表しています。
(This means that "社会に出たらすぐ勉強しなくなる" or that "社会に入った瞬間に勉強と言う物をしなくなる".)

Could somebody provide me some examples to figure it out?

いくつかの例を提供します。(I will show you some to explain:)

• 私が声をかけた途端、彼は叫んだ (As soon as I called out to him, he screamed.)

• 家の中は暖かかったが、外に出た途端気温が一気に下がった
  (It was warm inside the house, but once outside, the temperature dropped dramatically.)

Answer 2

とたん（途端）is used like:

• "as soon as (I said something)"
• "just as (I said something)"
• "the instant (I said something)"
• "the moment (I said something)"

The construction is:

[verb in plain past] とたん、next sentence

彼はそう言ったとたん、話し終わった。

The instant he said that, he stopped talking.

Sometimes とたんに is used. Then you don't use a comma.

仕事が終わったとたんに殺されるんだ。

As soon as they are done with their work, they will be killed. ;(

Wheter you use とたん or とたんに doesn't matter. The meaning wont change.

Also, to your original question: Wheter the second phrase is in the past or not won't change the meaning of とたん. It will simply only change the meaning of the sentence.

Like for example:

As soon as they are done with their work, they will be killed.
As soon as they were done with their work, they were killed.