Question

1- what is the relation between the terminal voltage drop and the resistor voltage drops?

2- how are the absolute potentials related to the voltage drop?

3- how are the resistor voltage drops related to the terminal voltage drop?

4- how are the resistor voltage drops related to the resistances.

5- how are the resistor currents related to the circuit current?

6- How are the resistor currents and resistances related?

7- how are the currents in the wires related to the currents in the resistors ?

8- what can you conclude about Currents in a series circuit? Is the circuit current the same as it was in the parallels circuit?why?

Answer 1

1. (EMF) - [(load current)* (internal resistance)] = terminal Voltage. The EMF is fixed, The load current, internal resistance and terminal Voltage may vary.

2. A value close to the EMF of the battery is normally what is indicated on a circuit drawing. The EMF of a 12 Volt battery is actually some what more than 12 Volts but it is normally shown as 12 Volts on a drawing. The range of the internal resistance of a battery is determined at the factory. The actual value of a given batteries`s internal resistance within that range is determine by the percent of full charge that the battery possesses at any given time. The more the battery is discharged the higher the batteries` internal resistance.

3. Terminal Voltage may be defined as the Voltage that exist between the two external terminals of a battery or any other electrical power supply. Terminal Voltage is not fixed. It varies with the variables given in the equation in paragraph 1.

4. The only time a batteries` terminal Voltage is equal to it`s EMF is when no load is connected to the battery. With no load the internal and external (load) current of the battery equals zero which means there is no Voltage drop across the internal resistance. This leaves the terminal Voltage equal to the EMF as shown in the equation in the equation in paragraph 1. Even when the load resistance equals the batteries` internal resistance a finite load current still exist. Therefore the Voltage drop across the internal resistance (load current times the load resistance) subtracts from the EMF as shown in the equation in paragraph 1 leaving the terminal Voltage less than the EMF.