At times many of you must have felt the need of spying on some body’s conversation over the telephone and wondered how to bug a telephone.
Morally it won’t be correct to eavesdrop on an individual’s personal discussion, but through electronics you can always and every time find a way of fulfilling your wishes no matter whether the act is ethical or not.
Though I won’t recommend using the present circuit for listening to somebody’s private talks, it can rather be used as a fun gadget for broadcasting a telephone conversation over the FM radio.
The circuit is very simple to build, so tiny in size that it easily fits inside the landline telephone itself. Once connected to the wires of the telephone line, it will immediately detect any conversation made over the particular telephone and convert them into FM signals. By carefully tuning your FM set, you should be able to listen to these speech signals wirelessly up to a radial distance of more than 10 meters.
The out put is distinctly clear and the listener should be able to hear even the whispers of the person conversing over the telephone.
It can also be used to record a conversation made over a telephone. So if you are thinking how to record a telephone conversation? The idea is simple. The signals aired from the circuit may be received by the FM radio of your mobile phone and easily recorded.