Mechanical Aids are more effective than teacher-made aids. They make great impact in the minds of the listeners. Mechanical aids require ample space and electricity. Some mechanical aids that can be utilized well in the classroom are Overhead projector, tape recorder, linguaphone records, radio and television.

Overhead projector is one of the important visual aids in the modern classroom. Overhead projectors are used to reflect what the teacher has written on a transparent plastic film before the class begins. For a class containing a huge crowd, overhead projector is of great use. In language teaching, it is useful and more convenient way in place of using chalkboard. In case of chalkboard work, the teacher stands in front of it while writing and thus his writing on the board is obstructed from the view of the students. This drawback can be overcome in the case of overhead projector. The teacher can write a poem on the transparency sheet and it can be reflected on the screen and students may be asked to memorize it in class. The transparency can be used to teach students to predict a word. For example, the teacher writes words slowly. The students should predict/ say words before they are written down by the teacher. This helps students remember words and their pronunciation.

   Tape recorder is very useful type of audio aid. It can serve many useful purposes in the teaching of English.
There are tapes available for good pronunciation, prose reading, poem recitation, stress, intonation etc. Tapes can be prepared with the personal interest and efforts of the teacher. The students may be asked to use those tapes. They can do so at home and also in the institution. It will improve their pronunciation. It can also help in listening to the native speakers of the language.
Tape recorder can also be used for learning spelling of the words. In the classroom to certain spelling tapes will help the students to learn spelling of difficult words; especially the ear-minded children get help, in this connection. The tape-recorder is very useful for self-criticism and self-education. A learner can speak and record his speech for listening to its further. This will rectify his problems with language. Thus, tape recorder functions as an important audio aid.

This is very useful audio aid in English teaching. Generally, it is an expensive aid but it is of great advantage in the classroom situations. There are records available on well known speeches. Listening to this type of records can imbibe speech abilities among the students. The linguaphone is a kind of gramophone designed especially for pronunciation practice, correcting speech disorders and teaching sounds and sound combinations. Even the teachers can benefit considerably from linguaphone records because they can listen to the sounds of the native speakers of English. Most of the Indian teachers of English have a defective pronunciation in English and suffer from regional influences of the mother-tongue. They can take the help of linguaphone record can improve their own pronunciation. Therefore they can help their students to overcome their speech difficulties.

Television is an important aid in the teaching of English. It has been described as ‘The queen of audio visual aids’ Unlike radio,in addition to the sense of hearing it appeals to the sense of sight There are two kinds of Educational Television. They are:
1. Open Circuit Television: It is the usual type of telecast by commercial or non –commercial stations
2. Closed Circuit Television: Selective telecast which can be tuned in only by specially equipped receivers.