When the blood pressure cuff is inflated, the blood flow is stopped. Slowly the cuff is decreased. When the technician starts to hear the blood flow, these are called Korotkoff Sounds. This pressure point defines the systolic pressure.
the problem is either you haven't plugged the microphone in properly or your microphone is broken and you will have to get a new one.
Sound is vibrations. It can be detected with a microphone. I grew up with a deaf family and would go to concerts with inflated baloons.
Radionics advocates believe that underlying causes of diseases emit radio-like frequencies that can be detected by their equipment.
The sound sensor provides an output signal voltage that responds to sound detected by a microphone. It will only respond to loud sounds.
The way that sound waves are detected in your ear or in a microphone are fundamentally the same. Your ear and a microphone both have a lightweight membrane that is sensitive to sudden changes in pressure. In the ear this is called an Ear Drum. By sensitive, I mean that high pressure pushes it and low pressure pulls it. It physically moves like the skin of a drum. This movement can be detected, in a microphone it is detected by attaching a magnet to the vibrating membrane, and having a loop of wire near the magnet, but not attached to it. When the magnet moves relative to the wire a voltage is induced in the wire. This is called Faraday's Law. In your ear the process of measuring is more complicated but is essentially based on measuring the vibrations of the eardrum.
In the microphone, there is a diaphragm, which converts the DJ's voice into an electrical signal. This signal is sent along the wire to the antenna, which broadcasts it into the ether. Your home radio receives the signal through its aerial, then converts the signal from an electrical signal to audio - which is detected by your ear.
It wasn't 'discovered' - it was invented. Scientists realised that speaking into a microphone creates an electrical charge. Hooking up a detector to the mic, they were able to activate a switch if a charge was detected.
Sound waves are detected by the fact that the waves can cause objects to vibrate. The vibrations from the sound waves must be converted into a signal and then amplified and processed. Your ear and a microphone are common detectors of sound.
Brachial Plexus injuries are caused by damaging of nerves in the shoulder. They can be detected by a loss or decrease in feeling, as well as decreased muscle function in the hand or arm affected.
There are many hidden recorders available that are disguised as common objects that won't be detected such as pens and alarm clocks. If you are going more low tech, place it somewhere out of sight like on a bookshelf or in a planter.
The human ear can detect sound waves, but it has limited range and sensitivity. Some might chose to use a microphone and an associated electronics package to detect sound. Sound that is too soft to be detected or at too high or low a frequency to be heard might be looked at on a screen where the sound picked up by the microphone is amplified and converted to a picture that is displayed to provide a visual representation of the sound.
How earthquake are detected and observe