Decision making circuits
- 2. 2 Decision-making Circuits? How can an electrical circuit make decisions?
- 4. 4 Electrical Source An electrical source is something that changes one form of energy into electricity like a generator, a battery or a photovoltaic (solar) cell.
- 5. 5 Electrical Load An electrical load is something that changes electrical energy into some other type of energy, like light, heat, sound or motion.
- 6. 6 Control Device A control device controls the flow of current through a circuit. Any type of switch or electrical contact is a control device…
- 7. 7 Open and Closed A control device can be in one of two states: OPEN…
- 8. 8 Open and Closed A control device can be in one of two states: OPEN or Closed
- 9. 9 Control… Every time we use electricity we use some type of control device, such as a switch, to decide when the load will be ON or OFF.
- 10. 10 “ON and OFF” is the basic control circuit, but as we add more control devices, we can make the circuit more complex. Depending on the state of the inputs and the logic of the circuits (how the inputs are connected) we can “decide” when the load will be ON and when it will be OFF.
- 11. 11 February 15, 2014 Truth Tables Truth tables show the behavior of logic functions using “true” and “false” or ones and zeroes. The output (load) is dependent on the state of the inputs and their relation to each other (series or parallel) and whether they are normally open or normally closed.. A B Load F F F F T F T F F T T T
- 12. 12 February 15, 2014 This is called: Control Logic
- 13. 13 February 15, 2014 Logic Functions The basic logic functions are AND, OR, NOT, NAND and NOR. Their names are descriptive of their behavior…. Here is a short video to illustrate this fact.
- 14. 14 Press PLAY to view video
- 15. 15 AND Logic And logic is only true when ALL elements are TRUE. For example, in my house to get to the kitchen from the front door I have to walk through the living room AND the dining room. An example electrical circuit would be foot-switch that must be held down in order for the joy-stick to activate the lift control in a scissor lift or boom lift: both must be activated for the control to work.
- 20. 20 AND Logic Basic AND logic uses normally open devices connected in series.
- 21. 21 OR Logic OR logic is true when ANY or ALL elements are TRUE. For example, when making brownies I can use butter OR margarine. An example electrical circuit would be an alarm circuit that is activated if the front door or the back door is open when the alarm system is armed.
- 26. 26 OR Logic Basic OR logic uses normally open devices connected in parallel.
- 27. 27 NOT Logic NOT Logic is when the output is opposite of the input. An example electrical circuit would be the refrigerator light that turns on when the door is open and turns off when the door is closed. This is also called negation or inversion.
- 30. 30 NOT Logic NOT Logic is a unary operator that only uses one normally closed device, as opposed to AND and OR which are binary operators acting on two or more devices.
- 31. 31 February 15, 2014 Control Circuits Using control logic we can build simple control circuits to very complex processes using many devices in many combinations. We can combine AND and OR and we can negate individual elements or entire functions using the NOT operator.
- 32. 32 February 15, 2014 Combination Logic There are many combinations of these basic logic functions that can be connected in a circuit. We will explore more complex combinations and their applications next…