Tell me about simple batteryt tests please

[001]

Hi

I put 360Ohm resistor and 9V battery in SERIES and read current (25mA is ok)
But someone told me what I must connect resistor in PARALLEL with battery and read VOLTAGE sag

[PhilipPeake]

Either will work, you can calculate one from the other.

In your case, you have 360 ohms across 9v. You see 25mA flowing, so you know the voltage (I*R) must be 9v.

Your load is not causing the voltage to drop, so your battery would appear to be ok.

[DaJMasta]

Since your circuit only has a source and a load, completing the circuit will make the load in series or parallel interchangeably, the terms really only apply when there is more than one element in the circuit.

Probably the beginner forum is a better place for this, since it's not about test equipment.