Batteries are used either as sole or as backup power for residential smoke detectors. Mains-operated detectors have disposable or rechargeable batteries; others run only on 9-volt disposable batteries. When the battery is exhausted a battery-only smoke detector becomes inactive; most smoke detectors chirp repeatedly if the battery is low. It has been found that battery-powered smoke detectors in many houses have dead batteries.
|
|
The drinking water supply used the lowest pressure, while the intermediate and the high pressure mains served as hydraulic power networks. The intermediate pressure mains operated at and by 1896 some of pipework had been installed. It was used for powering 130 Schmid type water engines with a gross power of . The high pressure network had an operating pressure of bar and had a total length of .
|
|
Australian radio sets usually had the positions of radio stations marked on their dials. The illustration is a dial from a transistorised, mains-operated Calstan radio, circa 1960s. (Click image for a high resolution view, with readable callsigns.) Norman Banks was one of Melbourne's (and Australia's) most prominent broadcasters at 3KZ (1930-1952) and 3AW (1952-1978). He is remembered for founding Carols by Candlelight, as a pioneer football commentator, and for hosting both musical and interview programs.
|
|
Dial from a transistorised mains operated Calstan radio, circa 1960s Call signs in Australia are allocated by the Australian Communications and Media Authority and are unique for each broadcast station. The use of callsigns on- air in both radio and television in Australia is optional, so many stations used other on-air identifications. Australian broadcast stations officially have the prefix VL- and originally all callsigns used that format, but since Australia has no nearby neighbours, this prefix is no longer used except in an international context.
|
|
Many retailers sell devices which exploit the discomforting effects of in-air ultrasound. These devices are usually combined with a motion sensor which is triggered by movement within the sensors range. This causes the device to emit high frequency noise which is uncomfortable to the cats, and inaudible to most humans (although they can still experience unpleasant subjective effects and, potentially, shifts in the hearing threshold). The devices are available in both battery and mains operated forms, the latter generally having a higher output, greater range and requiring less attention.
|
|
After its closure, the tunnel gained a new purpose as a route for hydraulic power mains operated by the LHPC and for water mains. It was damaged during the Second World War when a German bomb fell in the river near Tower Pier in December 1940, and exploded on the river bed very close to the tunnel's roof. The shock of the blast compressed the tunnel radially, reducing its diameter to at the point of impact, but the tunnel's lining was not penetrated. During the course of repair work, it was found that – apart from the bomb damage – the tunnel had survived seventy years of use in excellent condition.
|
|
Japanese manufacturer Akai, however, persisted with cross-field bias and successfully marketed portable and mains- operated machines featuring the cross-field system. Different amplitudes of bias field are optimal for different types of tape, so most recorders offer a bias setting switch on the control panel, or, in the case of the compact audio cassette, may switch automatically according to cutouts on the cassette shell. Ferric-based tapes require the lowest bias field, while chrome-based tapes (including the pseudo-chromes) requiring a higher level, and metal-particle tapes requires even more. Metal-evaporated tape accepts the highest level of bias, but it is mostly used for digital recording (which does not use bias, as the non-linearity is not a major problem).
|
|
100px 100px 100px 200px Commonly known as a "figure-8", "infinity" or "shotgun" connector due to the shape of its cross-section, or less commonly, a Telefunken connector after its originator. This coupler is often used for small cassette recorders, battery/mains-operated radios, battery chargers, some full-size audio-visual equipment, laptop computer power supplies, video game consoles, and similar double-insulated appliances. A C8B inlet type is defined by the standard for use by dual-voltage appliances; it has three pins and can hold a C7 connector in either of two positions, allowing the user to select voltage by choosing the position the connector is inserted.Australian/New Zealand Standard AS/NZS 60320.1:2004, Appliance couplers for household and similar general purposes Part 1: General Requirements (IEC 60320-1, Ed. 2.0 (2001) MOD).
|
|