Current and free charge carriers

Evolution of the understanding of electric current 

Electrolyte 

Electric charge         

Electric  current  is one point property       

Conventional current               

Drift speed            

Units

 Sign conventions 

Circuits:

1. Currents are variables       Direction of the currents is like orientation of the coordinate system       After solving Kirchhoff's 1st and 2nd laws re-label the currents to be positive

2. The meaning of equivalent resistance         Resistors in parallel and in series            Network of resistors        Voltmeter         Ampmeter

3. Voltage divider        V1 / R1 = V2 / R2        Measuring light and temperature          Rheostat 

4. Complex circuits