Electroacoustic device which generates a varying current in acidulated water
A water microphone or water transmitter is based on Ohm's law that current in a wire varies inversely with the resistance of the circuit. The sound waves from a human voice cause a diaphragm to vibrate which causes a needle or rod to vibrate up and down in water that has been made conductive by a small amount of acid. As the needle or rod vibrates up and down in the water, the resistance of the water fluctuates which causes alternating current in the circuit. For this to work, the resistance of the water must vary substantially over the short distance the needle or rod vibrates. Acidulated water works well because only a small amount of acid is added. If one millimeter of acidulated water has a resistance of 100 ohms, two millimeters would have 200 ohms which would produce enough alternating current to transmit audio signals in thousands of feet of wire. Mercury will not work because the resistance of one millimeter of mercury is less than a tenth of an ohm and vibration of a needle in mercury would produce negligible alternating current.
Elisha Gray reasoned that a metal rod vibrating up and down in acidulated water would alternately lengthen and shorten the small distance between the bottom end of the rod and a metal plate at the bottom of the glass container holding the water. This is the invention described in Gray's caveat.[1] When Alexander Bell's lawyer heard that Gray had described a vibrating rod in a liquid to vary the resistance, he added a claim for variable resistance in a draft of Bell's unfiled patent application and added an additional seven sentences that mentioned mercury as the liquid.[2] The lawyer knew that Bell had experimented with a wire dipped in mercury to provide a flexible electrical switch.[3]
On March 10, 1876, when Bell and Watson tested their first successful water transmitter, Bell used a needle in the water to minimize the inertial mass moved by the diaphragm and relied on variable resistance in the meniscus of the water on the needle. The depth of the needle made little difference.
Other minor variations and improvements were made to the liquid microphone by Majoranna, Chambers, Vanni, Sykes, and Elisha Gray.
Although the water microphone was commercially impractical, the variable resistance feature inspired Thomas Edison to experiment with dry carbon (graphite and amorphous) to provide the variable resistance. The Edison transmitter with later improvements was used for more than 60 years.
^Evenson, pages 222-223
^Evenson, pages 195-196
^See Bell's US Patent 161,739 page 3 left column beginning "tween the overhanging end..."
A watermicrophone or water transmitter is based on Ohm's law that current in a wire varies inversely with the resistance of the circuit. The sound waves...
A microphone, colloquially called a mic (/maɪk/), or mike, is a transducer that converts sound into an electrical signal. Microphones are used in many...
The Microphones were an American indie folk, indie rock, and experimental project from Olympia, Washington. The project was founded in 1996 and ended...
for a liquid microphone. The device used a metal needle or rod that was placed – just barely – into a liquid conductor, such as a water/acid mixture....
The carbon microphone, also known as carbon button microphone, button microphone, or carbon transmitter, is a type of microphone, a transducer that converts...
A hydrophone (Ancient Greek: ὕδωρ + φωνή, lit. 'water + sound') is a microphone designed to be used underwater for recording or listening to underwater...
transmitter in 1879. Early telephones were technically diverse. Some used a watermicrophone, some had a metal diaphragm that induced current in an electromagnet...
telephone in 1876. Elisha Gray, 1876, designed a telephone using a watermicrophone in Highland Park, Illinois. Tivadar Puskás proposed the telephone switchboard...
sometimes referred to as an open microphone or (in aviation) a stuck mic, is in general an apparent error in which a microphone is switched on or remains on...
The Microphones were an American indie folk, indie rock, and experimental band, founded and fronted by Phil Elverum. The band has released 5 studio albums...
Invention of the telephone Timeline of the telephone The Telephone Cases Watermicrophone Shulman 2008. "What is a Synthesizer and how does it work? |". Playpiano...
by a sound wave. In air, sound pressure can be measured using a microphone, and in water with a hydrophone. The SI unit of sound pressure is the pascal...
condenser, an electrical device that stores energy Condenser microphone, a capacitor-based microphone that converts sound waves into an electrical signal Synchronous...
surround microphones are backwards facing cardioid microphones, that are placed 40 cm back from the L and R microphones. The L, R, LS and RS microphones pick...
for allowing the use of a microphone in a synagogue that is turned on before the start of Shabbat on the basis that a microphone does not create a human...
IP67-certified rating in dust and water resistance. The phone takes USB-C; much like other recent phones. There are two microphones; the first is between the...
mobile phones use a multi-microphone design to cancel out ambient noise from the speech signal. Sound is captured from the microphone(s) furthest from the...
released his debut studio album Greatest Hits in 2007 and his second album, Microphone Champion in 2009, both independently; while his third studio album Doin'...
public address system (or PA system) is an electronic system comprising microphones, amplifiers, loudspeakers, and related equipment. It increases the apparent...
theory – Understanding of gas properties in terms of molecular motion Microphone – Device that converts sound into an electrical signal Orders of magnitude...
an unlockable bootloader. In 2019, a class action lawsuit over faulty microphones in some devices enabled Pixel owners to claim up to $500 in compensation...
featured a control capsule in-line with the left earbud's wire with a microphone and a single button, actuated by squeezing the unit, which can be programmed...
megaphone cannot be restricted. Long range acoustic device (LRAD) Water Talkie Human microphone Montgomery, Henry C. (1959). "Amplification and High Fidelity...
built-in microphone and on-cord controls Ultimate Ears 500: single dynamic driver Ultimate Ears 500vi: identical to 500, but adds built-in microphone and on-cord...
Global Information