I am a complete electronics newbro. I am looking at building a small circuit for a couple of home made modelling projects.

I am following http://www.instructables.com/id/ThrobbingFading-LED-with-555-Timer/step6/Lets-Solder/ which by my estimation has a great step by step to build a hardware driven fade in/out LED circuit.

My only question is what sort of power supply can I run this from? I am looking for as small as possible (but still readily available), I know I can run an LED off a traditional watch battery, would that also work here?

Sorry about the caveman terminology, again I am very new to this.


The person in the video you linked (http://www.instructables.com/id/ThrobbingFading-LED-with-555-Timer/step6/Lets-Solder/) used a 9V battery to power the circuit. You can do that as well.

The limiting factor here is your 555 chip, it will need a minimal voltage to run correctly (and also a maximal voltage you cannot exceed).

By far the most common chip voltage supply input range from 4.5V to 16V. For example: http://www.ti.com/lit/ds/symlink/lm555.pdf

You can use any supply the can give the voltage in that range.

Remember that if you use a battery the "smaller" it is the shorter will be the running time of your design.

Take care, Source: I'm an EEEngineer

  • \$\begingroup\$ Examples of power sources: 4xAA batteries in a series = ~6V. USB charger = 5V. Two lithium coin batteries (CR2032) in series = ~6V \$\endgroup\$ – Gomunkul Jul 18 '15 at 16:23

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