# Low Power Timer That Becomes Dead Short at Intervals

(Edited based on feedback)

There are two parts to this question:

1) Does the thing I describe below exist already in pre-packaged form, IC, etc.

2) Is the thing common enough to have a name that I can google more about?

And here's the thing:

I want a component that can be connected to a power supply that provides 5V at up to 1W. The component acts as a low power (<<1mA drawn), high resistance timer for interval N and as a dead short (to an output line) for interval M, where N would vary from minutes to days, and M would vary from milliseconds to perhaps up to a second. Intervals M and N would alternate indefinitely, input line would always receive voltage/power, and the external load would always be attached to the output line.

If I've left something out that would help answer this, please point that out, I'm an electronics noob so this may be underspecified as it stands.

Also, the specific numbers I used aren't hard and fast, but they illustrate the operation I want. Any solution should behave conceptually the same if the power supply varies, e.g. 12 V at 10 W, etc.

Context for this question is that I am trying to find a component that can take power input from either/both a storage unit or generator (both in the same range of voltage/power) and supply this to the load (solenoid) only at the active (M) intervals, while during the off intervals (N) the generator stops supplying power and the storage provides enough to run the low power counter until the next on interval. When transitioning from off to on intervals, the storage has enough stored energy to supply the load for a short period at which point the generator kicks in. None of this is part of the component in question, just providing this context by request, and in case it helps answer.

• I'm struggling to think of a non-malicious use for such a thing. Commented May 10, 2018 at 21:43
• How much current is expected to be shorted to ground during interval M? What is the nature of that load (inductive, resistive, etc.)? Commented May 10, 2018 at 21:45
• The load is going to be a normally closed solenoid valve, which has a range of input voltage/current, but let's use 8V, 200mA for discussion purpose. Commented May 10, 2018 at 21:50
• please provide a diagram .... your description is muddy Commented May 10, 2018 at 21:55
• How do you want to adjust the two intervals? For both intervals, what is the smallest time step required? Commented May 11, 2018 at 3:31

Your question is rather garbled.

I want a component that accepts 5V at 1W, and acts as a low power (<<1mA drawn).

A component that draws 1 mA at 5 V will have a power consumption of 5 x 1m = 5 mW. What does 1 W have to do with it?

Any solution should behave conceptually the same at 12 V or 10 W, etc.

You have the same confusion in this statement.

If you edit your question to explain the purpose of your proposed device you may get more helpful answers. Otherwise your question is likely to be closed as "unclear what you are asking".

• Edited to clarify based on your points, and added some context as to what I am trying to do Commented May 10, 2018 at 22:19

As I read your requirements, a relay (essentially an electrically-operated switch) would do the switching you require. (your description initially sounded like you want to connect the power source to ground for short periods, rather than supply power to a load (your solenoid) for short periods).

The relay can probably best be controlled by a microcontroller (Arduino or similar) that can be programmed to provide the required time intervals.