Why does this tiny electronic flasher circuit use so much energy?

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tim_ber

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If you are after a single flashing LED, you can buy them from most good electronics shops / suppliers for not a lot.
Why add the complication of a timer circuit?

A single flashing LED with a series resistor to limit the current would consume less than 10mA when it is on.

Regards

Ian
 
ianfr said:
If you are after a single flashing LED, you can buy them from most good electronics shops / suppliers for not a lot.
Why add the complication of a timer circuit?

A single flashing LED with a series resistor to limit the current would consume less than 10mA when it is on.

Regards

Ian
Click to expand...

Yes, thanks for that.

But I have 100s of LEDs around plus 555s and all the other parts and to be honest, I am more interested in learning WHY this circuit draw so much energy.

It seems a nice circuit because rate of flash can be changed too. Also, changing one resistor can make a huge difference to brightness of LED, so if using Nichia LEDs, you can achieve quite an affect. Can power up to 6 LEDs too.
 
I can't see that that should be drawing more than say 100ma tops -and more likely half that. Faster flashing rates will of course draw more power
 
tim_ber said:
https://www.google.co.uk/search?q=l...firefly-diorama%2Ffirefly-diorama.htm;410;448

Hopefully the link shows a 9V duracell battery and 555 timer etc. The website states that 12V can be used.

Very simple circuit using a 555. A single LED. Yet it took a lot out of a single 12V battery in just over 24 hours.

Does this circuit use a lot of juice? My battery is of average to good state.-; not brand new.

Thanks
Click to expand...
Which circuit are you referring to? You linked to an image search results page.
 
elton said:
Which circuit are you referring to? You linked to an image search results page.
Click to expand...

I thought the link would go straight to the image showing something that looks similar to a 9V Duracell battery.

If not, scroll down until you see the image as described, plus one capacitor a 3 resistors.

After the previous comments about the low draw, I will do a proper test and measure the draw.

Thanks, all
 
As said the 555 is a bipolar transistor IC device so in itself draws current in the transistors in addition to the current of the LED.
If you were to use a 4011 CMOS IC it has 4gates in it then the current will be incredibly low apart from the current drawn by the LED.
The CMOS IC is of course what is used in a digital watch where current drain must be low.
CMOS technology uses in effect 2 FET transistors in series. Being FET they need very tiny current mostly a voltage to switch on. One FET turns on as the other turns off so only a small current in transition and no standing current as in a classic transistor with resistive load. Just add 4011 to the search parameters of the page you linked to. You can do the same thing with 4001 or many other ICs. As they have 4 gates and you only need 2 gates for a flip flop for flashing the LED the next step is to use the other 2 gates to pulse the flashing on and off ie at 10 sec period. All good fun have a fiddle you might even find a job for it on the boat.
olewill
 
The op 'has a bunch of LED's and 555's' so suggesting all sorts of other circuits is not answering the question.

The answer is either that the circuit is 'not' responsible for the power drain ( If an NE 555 was sinking a couple of hundred ma it will be damned hot ). If it's not hot then go look for your current drain somewhere else! ( as you have said you would ) OR something is wired wrong. An electrolylic cap backwards or something?

If you are using 5mm leds they probably can't stand more than 30mA at most.

NE 555 should consume about 20 mA at 12v the old CMOS equivalents like the ICM7555 would run on 60uA!
 
Last edited:
thanks guys, a lot learned there.

nothing hot - current drain was found to be something running in background.

interesting info on the 4011 CMOS IC

cheers a lot
 
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