PRELIMINARY: these activities should be completed before the first lab session for lab 2 lab and written into your log book. Draw the simple circuit opposite into you log book and calculate the voltage at each point, relative to zero volts, with the switch open, and then with the switch closed. Calculate the current flowing with the switch open and closed. In your log book state the role of the resistor. State what would happen if it was zero ohms, The NAND gate circuit opposite is the first attempt to design a circuit that will test the logic function of a real HCOO NAND gate. The idea is that the red LED lights for a high output, and the green lights for a low output. The circuit has several severe problems do not build it. Work out the currents and voltages in each element and explain why the circuit cannot work and any problems. This must be written in your log book. Solution Hello. For the first circuit, first, we will list the nodes of the circuit: Node A, between power and resistance of 270 Ohms; Node B, between reistance and Diode; Node C, between diode and Switch; and Node D, between switch and Ground ( or Reference) . When the switch is OFF: The node A always has 5V , This node is always connected to the source. The node B has 5V, but not always he has 5V. The node C has 5V, While the switch is off, the voltage in each Node, unless the Node D, are 5V. The node D always has 0V, this node is always connected to the reference or ground. The current flowing through the circuit is 0 A. To not close the circuit, no current flows through the circuit When the switch is ON: The node A has 5V The node B has 0.7V (approximately). This node assumes the same voltage that is biased diode. The node C and D has 0V, they nodes are connected to the same ground. The current flowing through the circuit is 15.9 mA (16 mA). This is so by Ohm\'s law: I= (V \\ R), so, I= (5-0.7)V \\ 270 I=16 mA. If the resistor 270 is disconnected, the circuit would be shorted, which could cause some damage to the diode. The circulating current without resistence is 18.5 mA, in theoric For the previous problem it was assumed that the voltage consumed by the diode is 0.7. For the second circuit: How the idea is that the red LED lights for a hight output, and the green lights for a low output. The circuit does not work properly due to the current flowing through the input NAND gate is very high, 0.5 A. The current flowing through the NAND gate output is 23.06 mA. The NAND gate cannot work good, because the current throught his input its to high .

1. PRELIMINARY: these activities should be completed before the first lab session for lab 2 lab
and written into your log book. Draw the simple circuit opposite into you log book and calculate
the voltage at each point, relative to zero volts, with the switch open, and then with the switch
closed. Calculate the current flowing with the switch open and closed. In your log book state the
role of the resistor. State what would happen if it was zero ohms, The NAND gate circuit
opposite is the first attempt to design a circuit that will test the logic function of a real HCOO
NAND gate. The idea is that the red LED lights for a high output, and the green lights for a low
output. The circuit has several severe problems do not build it. Work out the currents and
voltages in each element and explain why the circuit cannot work and any problems. This must
be written in your log book.
Solution
Hello.
For the first circuit, first, we will list the nodes of the circuit: Node A, between power and
resistance of 270 Ohms; Node B, between reistance and Diode; Node C, between diode and
Switch; and Node D, between switch and Ground ( or Reference) .
When the switch is OFF:
The node A always has 5V , This node is always connected to the source.
The node B has 5V, but not always he has 5V.
The node C has 5V,
While the switch is off, the voltage in each Node, unless the Node D, are 5V.
The node D always has 0V, this node is always connected to the reference or ground.
The current flowing through the circuit is 0 A. To not close the circuit, no current flows through
the circuit
When the switch is ON:

2. The node A has 5V
The node B has 0.7V (approximately). This node assumes the same voltage that is biased diode.
The node C and D has 0V, they nodes are connected to the same ground.
The current flowing through the circuit is 15.9 mA (16 mA). This is so by Ohm's law: I= (V
R), so, I= (5-0.7)V 270
I=16 mA.
If the resistor 270 is disconnected, the circuit would be shorted, which could cause some damage
to the diode.
The circulating current without resistence is 18.5 mA, in theoric
For the previous problem it was assumed that the voltage consumed by the diode is 0.7.
For the second circuit:
How the idea is that the red LED lights for a hight output, and the green lights for a low output.
The circuit does not work properly due to the current flowing through the input NAND gate is
very high, 0.5 A. The current flowing through the NAND gate output is 23.06 mA. The NAND
gate cannot work good, because the current throught his input its to high