Geplaatst op 27 oktober 2006 - 17:22
Is er iemand die hierbij kan helpen?
Geplaatst op 27 oktober 2006 - 18:04
nogal kort en beperkt hŤ
The Humble History of Doorbells
With the advent of the front door, came the need to alert those inside when a visitor arrived. A simple knock on the door or ring of a hanging bell worked fine, until electricity came along. The market was ripe for an electronic doorbell! The first electronic doorbells were buzzer models that elicited a noisy buzzing or clanking sound when used. In the early 1930's, there was a surge of patents filed for musical door chimes. Many of these early designs featured bells or chimes that were struck by solenoids when activated. As with many innovations, these pleasant-sounding doorbells were considered fashionable luxury items that should be displayed prominently in a home or even given as a gift.
By the late 1960's, doorbells had lost much of their novelty and the only large producer left in the chime business was Nutone Doorbells. Today, there are numerous manufacturers who make basic and decorative doorbells
Dus in 1878 hadden telefoons al een belsysteem
On August 1, 1878 Thomas Watson filed for a ringer patent. Similar to Henry's classroom doorbell, a hammer operated by an electromagnet struck two bells. Turning a crank on the calling telephone spun a magneto, producing an alternating or ringing current. Previously, people used a crude thumper to signal the called party, hoping someone would be around to hear it. The ringer was an immediate success.
Joseph Henry staat blijkbaar te boek als de uitvinder van de elektrische bel.
en nou kun je zelf wel verder zoeken zeker?
help ons dan eiwitten vouwen, en help mee ziekten als kanker en zo te bestrijden in de vrije tijd van je chip...
0 gebruiker(s) lezen dit onderwerp
0 leden, 0 bezoekers, 0 anonieme gebruikers
- Hier ook uw vacature? 06-14