SpiceCircuit is Free and does NOT contain any adverts or in-app purchases.  The app does NOT collect, store, record, or send any data.  The app does NOT access any other phone information (like contacts or bookmarks).
The app only performs pure technical "simulation of a user entered circuit", and thus contains NO other extraneous functions or information that would be unsafe for minors.

APP PERMISSIONS

Access External Storage
This is required to write Spice NETLIST files to a public directory, so an external SPICE simulation package (like AIMSpice) can load this netlist file for simulation.  This "SpiceCircuit" app can then load in the stored results of the external Spice (AIMSpice) simulation, for displaying results on the circuit.

Internet Access
The INTERNET permission is required for development, for deploying the application for testing to tethered android devices.  However the application does not collect, record, or send any data.