The above figure is a reference for buck-boost design. In normal product design, the supply voltage fluctuates frequently. For example, the voltage before and after the battery is different, just falls in the middle of the LED forward voltage value that needs to be driven. This IC can solve this buck-boost problem very well!
LED driver chip TPS6115 typical application circuit
A siren is a loud noise-making device. Civil defense sirens are mounted in fixed locations and used to warn of natural disasters or attacks. Sirens are used on emergency service vehicles such as ambulances, police cars, and fire trucks. There are two general types: pneumatic and electronic.
Many fire sirens (used for calling the volunteer fire fighters) serve double duty as tornado or civil defense sirens, alerting an entire community of impending danger. Most fire
sirens are either mounted on the roof of a fire station or on a pole
next to the fire station. Fire sirens can also be mounted on or near
government buildings, on tall structures such as water towers,
as well as in systems where several sirens are distributed around a
town for better sound coverage. Most fire sirens are single tone and
mechanically driven by electric motors with a rotor attached to the
shaft. Some newer sirens are electronically driven speakers.
Fire sirens are often called "fire whistles", "fire alarms", or
"fire horns". Although there is no standard signaling of fire sirens,
some utilize codes to inform firefighters of the location of the fire.
Civil defense sirens also used as fire sirens often can produce an
alternating "hi-lo" signal (similar to emergency vehicles in many
European countries) as the fire signal, or a slow wail (typically 3x) as
to not confuse the public with the standard civil defense signals of
alert (steady tone) and attack (fast wavering tone). Fire sirens are
often tested once a day at noon and are also called "noon sirens" or
"noon whistles".
The first emergency vehicles relied on a bell. Then in the 70s,
they switched to a duotone airhorn. Then in the 80s, that was overtaken
by an electronic wail.
Piezo Alarm,Siren And Alarm,Piezo Buzzer Siren,Piezo Buzzer Alarm Siren
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