Answers for Unit 7

Task03

1. Sensors are used to monitor the pressure and temperature of a chemical solution stored in a vat. The circuitry for each sensor produces a HIGH solution when a specified maximum value is exceeded. An alarm requiring a LOW voltage input must be activated when either the pressure or the temperature (or both) is excessive. Draw a truth table with the desired inputs and outputs and from that design a circuit for this application.

Two inputs → P T
P - Pressure
T - Temperature

If either the pressure or the temperature or both parameters increases the specified value, a high voltage must be produced. Those high voltages must be converted to low voltages and supplied to the alarm to make rings.

|P |T |Output (A) |
|0 |0 |0 |
|0 |1 |1 |
|1 |0 |1 |
|1 |1 |1 |

_
→ F= PT _
→ F= PT

→ F= PT

_ _
F= PT+ PT+ PT _ _
F= PT+ PT+PT _ _
F= P (T+T) + PT _
F= P + PT

P T

_ F= P + PT

2. Digital circuit has three inputs A, B and C and three outputs X, Y and Z.The truth table is given below. Determine separate Boolean expressions for X, Y and Z and draw the logical diagram.

|C |B |A | X | Y | Z |
|0 |0 |0 |1 |0 |0 |
|0 |0 |1 |0 |1 |0 |
|0 |1 |0 |0