1. ELECTRICAL COMPONENTS and CIRCUITS Instrumental Analysis II CTEC 1345

2. Introduction Electrical terms and types of circuits will be covered in this section.

3. Agenda Current Voltage Resistance Power Energy Ohms Law Series and Parallel Circuits

4. ELECTRICAL CHARGE ELECTRICAL CHARGE coulomb = 6.24 x 10 18 electrons

5. CURRENT Current is the flow of electrons (I) and is measured in amperes (A)

6. CURRENT Ampere = number of e - passing a given point in one second 1 amp = 1 coulomb/sec An ammeter measures current

7. VOLTAGE Voltage is the difference of potential energy that forces electrons (current) to flow in a circuit.

8. VOLTAGE Voltage is proportional to the difference in electrical energy between two points.

9. VOLTAGE Voltage is measured in volts (v) One volt is required to force 1 amp through 1 ohm of resistance. A voltmeter measures voltage.

10. RESISTANCE Resistance is the opposition to the flow of electrons (current).

11. RESISTANCE Resistance is measured in ohms (  )

12. RESISTANCE Resistance is due in part to the nucleus of each atom resisting the removal of their electrons and the collision of the electrons with each other during flow.

13. RESISTANCE An ohmmeter measures resistance.

14. POWER Electrical power (P) – the amount of electrical energy converted to another form of energy in a given length of time.

15. POWER Electrical power is measured in watts.

16. POWER P = VI P = power V = voltage I = amperes

17. ENERGY When electrons are in motion they have kinetic energy.

18. ENERGY Electrical energy is measured in joules.

19. ENERGY E = VIT E = energy V = voltage I = amperes T = time

20. ENERGY An example of everyday use of electrical energy is the kilowatt hour.

21. ENERGY Power can be substituted for VI in the formula and divided by 1000 to convert to kilowatts. E = Pt/1000

22. ELECTRICAL CIRCUITS All electrical circuits contain the following three parts: – voltage source – load (resistance) – conductors for current

23. OHM'S LAW V = IR V = voltage I = amperes R = resistance

24. SERIES CIRCUIT

25. current ( I T ) remains the same throughout the entire circuit.

26. SERIES CIRCUIT V T = I T R T The total voltage (V T ) is calculated from Ohm’s Law using the total resistance (R T ) and the total current (I T ) of the series circuit.

27. SERIES CIRCUIT In a series circuit with more than one load

28. SERIES CIRCUIT the total resistance ( R T ) is the sum of the individual resistances.

29. SERIES CIRCUIT R T = R 1 + R 2....

30. SERIES CIRCUIT the total voltage ( V T )is the sum of the individual voltages across each load.

31. SERIES CIRCUIT V T = V 1 + V 2.... V 1 = R 1 (I T ) = R 1 (I 1 )

32. SERIES CIRCUIT V T = V 1 + V 2.... V 1 = R 1 (I T ) = R 1 (I 1 )

33. PARALLEL CIRCUIT A parallel circuit consists of individual series circuits attached to the same voltage source.

34. PARALLEL CIRCUIT The current through an individual series circuit may be different than the current flowing through the other series circuits.

35. PARALLEL CIRCUIT I T = I 1 + I 2 +.... The total current (I T ) is the sum of the individual currents flowing through each series circuit.

36. PARALLEL CIRCUIT The voltage across each series circuit is the same. V T = V 1 = V 2 =....

37. PARALLEL CIRCUIT The total resistance (R T ) of the parallel circuit is less than the total resistance of any individual series circuit.

38. PARALLEL CIRCUIT

39. The individual currents in a parallel circuit are calculated the same as in a series circuit.