160
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.
Components required:
1 x 2N3904 tran-
sistor, 2 x 1N4148
silicon diodes,
1 x BAT85 Schottky
diode, 1 x red LED,
1 x 1 k
Ω
resistor,
1 x 10 k
Ω
resistor,
2 x 22 k
Ω
resistors,
1 x breadboard, 1 x 9V
battery with clip con-
nector
Fig. 2.135:
NAND gate
with LED
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.
Summary of Contents for ELECTRONICS EXPERIMENTS BOX
Page 4: ......
Page 265: ...267 Fig 3 56 Cir cuit 56 Audio limiter Fig 3 57 Circuit 57 Amplifier for a storm detector...
Page 269: ...271 Fig 3 64 Circuit 64 Stabilizer for 1 9 V Fig 3 65 Circuit 65 Stabilizer for 2 5 V...
Page 275: ...277 Fig 3 80 Circuit 80 Quiztimer 30 seconds Fig 3 81 Circuit 81 Handy diode tester...
Page 315: ...317 Fig 3 179 Circuit 179 HF generator 150 kHz Fig 3 180 Circuit 180 HF generator 420 kHz...
