Nand Gate - Maker Factory ELECTRONICS EXPERIMENTS BOX Manual

The high state of the inputs is caused by closing the respective switch. If the switch is open, the input is
low. Such a circuit with the behaviour described above is known in digital electronics as NOR gate. A tablet
or notebook PC contains tens of thousands of those gates.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.134.

2.63 NAND gate

Circuit 135: NAND gate with LED
Setup information
Install the transistor, the four diodes and the four resistors as shown in Fig. 2.135. Then insert the four
jumper wires followed by the jumpers, which serve as switches (shown dashed). For your guidance, we
have labelled the switches with high E1, low E1 and high E2, low E2 Check the placement on the board
again and only then connect the battery.
Experiment
If everything is wired correctly, both "switches" are in the low position. The potential at the output is high;
the red LED is lit. The following table, also called truth table, shows what will happen now at the different
switch states.
160
Components required:
1 x 2N3904 tran-
sistor, 2 x 1N4148
silicon diodes,
1 x BAT85 Schottky
diode, 1 x red LED,
1 x 1 kΩ resistor,
1 x 10 kΩ resistor,
2 x 22 kΩ resistors,
1 x breadboard, 1 x 9V
battery with clip con-
nector
Fig. 2.135: NAND gate
with LED