help!!!

Hey guys!

i need some quick 411 on the 555 timer for the project i'm doing "British Police Siren" using two 555 timer ICs, as part of my school project.

help pls.

I just copy / pasted "555 British Police Siren" into Google. Sure enough, you are right, it does use two 555s.
Mind you, I have no idea what "quick 411" is.

Try not to use slang on an international forum. I think 411 is a phone number for information.

at http://english.cxem.net/home/home63.php ( http://english.cxem.net/home/home63-1.gif ) is a shematic for "British Ploce car Alarm"...
you can use my pbc for this...

Hi Yakubu62

There're many manufacturers of the 555. However, most of them should be pin compatible i.e the DIL-8 package. The 555 timer IC comprises of an interconnection of 23 transistors, 2 diodes and 16 resistors.
The 555 basically can be used for three types of operations:
Monostable - timer - where the output (pin 3) goes high for a certain time and returns to its original value
Bistable - flip-flop,
and Astable multivibrator mode of operation - an oscillator.

The mode in which your 555 works depends on the cct configuration. The 555 outputs the pulse depending on an external Resistor-Capacitor values.
and whether you connect pin 6 with pin 2 or not.

Plus point of the 555 is that it can source or sink upto 200milliamps of current so it can drive lamps and relays directly!!
remember current can kill!

The IC was designed and invented by Hans R. Camenzind. It was designed in 1970 and introduced in 1971 by Signetics (later acquired by Philips). The original name was the SE555/NE555 and was called "The IC Time Machine".
It is still in wide use, thanks to its ease of use, low price and good stability.

try wikipedia for some "quick 411" on the 555, it had a Java simulation of the oscillator cct.

there was also a good 555 tutorial by Tony van Roon, search for it.