# Conventional current, electron flow and ammeter

¤The statement above this circuit in my book reads 'the (conventional) current should flow into the ammeter through the positive red terminal and leave through the negative black terminal', as the switch is open here, in a real setup ammeter would not show the electric current measurement as the current won't be able to pass to it, so why do we still use Conventional current,isn't it actually wrong?

• leycha, I'm not sure I understand your question. To be clear, there is zero current (conventional current or electron current) through the ammeter when the switch is open. I don't think that the book is saying otherwise. Nov 6, 2020 at 16:21
• Why not? Because if current flows from positive terminal then current is passing through the ammter in that circuit....? Nov 6, 2020 at 17:06
• ieycha, (1) in the circuit pictured, the switch is in series with the ammeter which means that the current through each is identical, (2) an open switch has zero current through (by definition), (3) thus the current through the ammeter is zero when the switch is open. Nov 6, 2020 at 18:40
• @ieycha I think the text is assuming "when the switch is closed". By "conventional current" it means as if it was positive charges; electrons themselves are negatively charged and flow the opposite way. Does that help? Nov 6, 2020 at 20:52
• Thank you! That helped a lot. Nov 7, 2020 at 8:49