I am working with a project that requires a PP9 Battery. However I am unable to get the same. Even Wikipedia says that such batteries are not found much nowadays. Can anyone suggest me an alternative to this battery?

 

What is the project, how much current does it need, and how long must it run on one battery charge?

ak

 

What is the project, how much current does it need, and how long must it run on one battery charge?

ak

It is the same electronic dice circuit...

 

How to find how much current it needs?

 

Just use an ordinary PP3. If you need longer run time, use a 6-cell AAA or AA holder.

 

Just use an ordinary PP3. If you need longer run time, use a 6-cell AAA or AA holder.

That would be great. But then what is the difference between these 2 batteries? Why does the circuit need pp9 battery?

 

The PP9 is larger and capable of sourcing more current. It was designed to provide the grid voltage for vacuum tube radios. There's nothing about your circuit that requires it. The theoretical maximum current draw for your circuit is less than 100mA.

 

The PP9 is larger and capable of sourcing more current. It was designed to provide the grid voltage for vacuum tube radios. There's nothing about your circuit that requires it. The theoretical maximum current draw for your circuit is less than 100mA.

Thanks a lot.
Please also tell me how to find the current requirement for a given circuit?

 

It's not simple. I made some estimates based on what components were there and the resistor on the common cathode connection of the display. You can get some good numbers from the data sheets for the components but breadboarding and measuring is the surest method.

That appears to be an old design. A newer one might use lower power components.

 

pp9 are still available , try ebay or amazon

 

pp9 are still available , try ebay or amazon

Yeah.. But they are hell lot costly.. Moreover if its only use is to run the circuit for some extra tym.. Then I think I will prefer pp3 instead. No offence

 

Yeah.. But they are hell lot costly.. Moreover if its only use is to run the circuit for some extra tym.. Then I think I will prefer pp3 instead. No offence

A common approach is to use up the battery, then when its spent carefully unpick the steel jacket and discard the innards.

Some people build a mains "battery eliminator" small enough to fit inside, Another approach is to fill it up with cylindrical Ni-Mh cells.

A popular trick with the old valve era HT batteries, was to build a SMPSU boost converter to run off a lower voltage pack. The vintage radio sites have some nice pictures of these built into emptied out battery jackets.

Its best to make sure the battery you buy has a metal jacket - but you can still pack the cardboard ones with rechargeable cells.