ElectroDroid for reference and calculations.
EveryCircuit for testing/simulation.
And with the recent Circuit Jam, which is a puzzle game, i feel like i have no more excuses to not learn Electronics.

These are the ones i find essential.
Please tell yours!

 

Here are the links to the ones i mentioned:

ElectroDroid Pro: https://play.google.com/store/apps/details?id=it.android.demi.elettronica.pro&hl=en
Every Circuit: https://play.google.com/store/apps/details?id=com.everycircuit&hl=en
Circuit Jam: https://play.google.com/store/apps/details?id=com.circuitjam&hl=en

I'm surprised no one replied yet. No Android users here??
To someone starting like me, in need of gereral guidance, i find these apps unbeatable, however i'm interested if there are some specialized/niche apps that are really good too.

 

I've used the free version of EveryCircuit and found it too weak to make me willing to buy the paid version, but if you have the paid version, I welcome a detailed review when/if you can post one.