alarm circuits - Electronic Circuits Projects Diagrams Free

wyl86 · 17th August 2007, 03:01 PM

how do i design a simple alarm circuit using 74HC14?

most ppl all recommend 555timer bt wat is e difference between 555timer n 74HC14?

**Nigel Goodwin** · 17th August 2007, 03:05 PM

One's a timer, and the other is a Hex inverting Schmitt trigger - which you use depends what you're trying to do, there are a great many different ways to make a simple alarm circuit.

hamm3rst0rm · 17th August 2007, 03:21 PM

555 is better and lot more cheaper..

**Nigel Goodwin** · 17th August 2007, 03:55 PM

Quote:

Originally Posted by hamm3rst0rm

555 is better and lot more cheaper..

Not if you want a Hex inverting Schmitt trigger!

audioguru · 17th August 2007, 05:46 PM

If you want a very simple alarm sound that is a continuous steady tone then use a 555.

But the 6 Schmitt Trigger inverters in a 74C14 or 74HC14 can make 6 different frequencies. One frequency can be changed slowly by one of the other slower frequencies with a diode or resistor, or the tone can be turned on and off and beeping with a diode gate.

Hero999 · 17th August 2007, 09:06 PM

555s do have the advantage of having 200mA of drive capability.

Gordz · 27th October 2007, 03:02 PM

You can do a *lot* more with a 7414 (or a CD40106) than you can with a 555, especialy if you have one handy, and you can drive a piezo sounder with it as well. Swings and roundabouts really.

audioguru · 27th October 2007, 07:25 PM

I have never seen a CD40106 but I have used a CD74C14 and an MC14584 which are also ordinary Cmos hex Schmitt-trigger inverters. Their supply is from 3V to 18V. Each part has its own threshold voltages.

A 74HC14 needs a supply from 2V to 6V.

reyarba · 27th October 2007, 07:46 PM

Try this, it might help

http://www.amazon.com/Electronic-Cir...dp/1419643991/

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17th August 2007, 03:01 PM	(permalink)
wyl86	alarm circuits how do i design a simple alarm circuit using 74HC14? most ppl all recommend 555timer bt wat is e difference between 555timer n 74HC14?

17th August 2007, 03:05 PM	(permalink)
Nigel Goodwin	One's a timer, and the other is a Hex inverting Schmitt trigger - which you use depends what you're trying to do, there are a great many different ways to make a simple alarm circuit. __________________ PIC programmer software, and PIC Tutorials at: http://www.winpicprog.co.uk

17th August 2007, 03:21 PM	(permalink)
hamm3rst0rm	opinion 555 is better and lot more cheaper..

17th August 2007, 05:46 PM	(permalink)
audioguru	If you want a very simple alarm sound that is a continuous steady tone then use a 555. But the 6 Schmitt Trigger inverters in a 74C14 or 74HC14 can make 6 different frequencies. One frequency can be changed slowly by one of the other slower frequencies with a diode or resistor, or the tone can be turned on and off and beeping with a diode gate. __________________ Uncle $crooge

17th August 2007, 09:06 PM	(permalink)
Hero999	555s do have the advantage of having 200mA of drive capability. __________________ I also post at the following sites: http://www.stop-microsoft.org http://www.heated-debates.com Screen name: Aloone_Jonez And http://www.silicontronics.com, same screen name as here.

27th October 2007, 03:02 PM	(permalink)
Gordz	You can do a lot more with a 7414 (or a CD40106) than you can with a 555, especialy if you have one handy, and you can drive a piezo sounder with it as well. Swings and roundabouts really.

27th October 2007, 07:25 PM	(permalink)
audioguru	I have never seen a CD40106 but I have used a CD74C14 and an MC14584 which are also ordinary Cmos hex Schmitt-trigger inverters. Their supply is from 3V to 18V. Each part has its own threshold voltages. A 74HC14 needs a supply from 2V to 6V. __________________ Uncle $crooge

27th October 2007, 07:46 PM	(permalink)
reyarba	Try this, it might help http://www.amazon.com/Electronic-Cir...dp/1419643991/ __________________ Intellin.org Get good electronic circuits reference books.