minimum requirements for a 555

[redepoch7]

I tried hooking up a 555 timer to two AA batteries.
It didn't work.

I tried google for minimum requirements for the 555 but I didn't find anything but links to the low power 555 (7555? 1555? are there many?).

I was wondering if anyone new what the minimum for this IC are?

 

[Reloadron]

I tried hooking up a 555 timer to two AA batteries.
It didn't work.

I tried google for minimum requirements for the 555 but I didn't find anything but links to the low power 555 (7555? 1555? are there many?).

I was wondering if anyone new what the minimum for this IC are?

I suggest you start with **broken link removed** You arent telling anyone what you want to do with the chip? The 555 timer has dozens of configurations for different applications. Minimum Requirments for what?

Additionally the MINIMUM Supply Voltage is 4.5 Volts so two AAA or AA cells won't work.

Ron

 

[redepoch7]

Hey Ron,

Thanks for the reply. I did look at the datasheet and I didn't see it (it was there I just looked right over it)... my mistake.

The 555 timer is being powered by the batteries in a keyboard. The project is to attempt to add some vibrato. So I guess it's a LFO application.

It is being patched into the timing resistor/potentiometer of the keyboard.

That's what is being attempted anyway.

Thanks again for the help!
N

 

[Hero999]

Yes, you need at least four AA cells, three AA cells won't last long and for optimum battery life more will do.

What are you doing with the 555 timer?

If you just want to make a simple astable, all you need is a couple of CMOS gates, for two cells the HC series is best.

 

[redepoch7]

I will definitely look into that.

Is the output the same as any other square wave generator?

I don't really know anything about gates. I guess it's time to start reading.

 

[k7elp60]

The CMOS version of the 555 will work down to 1.5V, such as the National Semiconductor LMC555N

 

[Hero999]

I will definitely look into that.

Is the output the same as any other square wave generator?

I don't really know anything about gates. I guess it's time to start reading.

I certainly is, try Googling for CMOS oscillator and clicking on the first link. Any CMOS inverting gates can be used: NAND, NOR or NOT.

CMOS oscillator - Google Search

 

[audioguru]

The 74HC14 oscillators in my 3V Ultra-Bright Chaser project still work when the 3V battery has dropped to 1.2V. Its supply current is very low so the battery lasts for a long time.
An ordinary 555 needs a supply of at least 4.5V and it has a fairly high supply current that will kill the battery soon.

 

[Hero999]

I don't know why so many people use the old 555 timer nowadays.

The only reason I can think of is because it can directly drive a 200mA load, which a CMOS IC can't do.

An HC IC can supply up to 50mA if several gate outputs are connected in parallel so if you want to drive a small relay you could use a hex inverter to make an oscillator and parallel the unused gates to drive a 50mA load.