Kits
›
Chips de la serie 74
RU
EN
ES
Contenido
Introduction
History: a computer from the catalogue
Lesson 0. Gates from transistors: for those who start from scratch
0.1. The idea: a transistor is a switch
0.2. Building
0.3. Check
Lesson 0 paste (Cmd+I)
Lesson 1. Logic in packages: 74HC00, 02, 04, 08, 32
1.1. The idea: a chip is a package with gates
1.2. The idea: free inputs go to ground
1.3. The idea: a latch from one chip
1.4. Building
1.5. Check
Lesson 1 paste (Cmd+I)
Lesson 2. Flip-flops in a package: 74HC74 and a frequency divider
2.1. The idea: a flip-flop with set and reset
2.2. The idea: six NANDs inside
2.3. The idea: a divider is a flip-flop that flips
2.4. Building
2.5. Check
Lesson 2 paste (Cmd+I)
Lesson 3. A counter in a package: 74HC390 and a stopwatch
3.1. The idea: ÷2 and ÷5 make ÷10
3.2. The idea: clocking on the fall
3.3. The idea: reset on a one
3.4. Building
3.5. Check
Lesson 3 paste (Cmd+I)
Lesson 4. A decoder in a package: 74HC138 and a running light
4.1. The idea: number → one wire
4.2. The idea: active 0
4.3. The idea: 4 → 16 from two 3 → 8
4.4. Building
4.5. Check
Lesson 4 paste (Cmd+I)
Lesson 5. A shift register: 74HC595 and 8 lamps over three wires
5.1. The idea: bits over one wire
5.2. The idea: a latch shows everything at once
5.3. The idea: the third state
5.4. Building
5.5. Check
Lesson 5 paste (Cmd+I)
Lesson 6. Bus buffers: 74HC244 and 74HC245
6.1. The idea: a bus and the third state
6.2. The idea: a buffer is a double inversion
6.3. The idea: both ways — two 74HC244
6.4. Building
6.5. Check
Lesson 6 paste (Cmd+I)
Lesson 7. An electronic dice
7.1. The idea: a counter to six
7.2. The idea: face number → dots
7.3. The idea: a fair roll
7.4. Building
7.5. Check
Lesson 7 paste (Cmd+I)
Summary
All the parts
Instructions in pictures
Lesson 2 in pictures
← Back to the lesson: Lesson 2. Flip-flops in a package: 74HC74 and a frequency divider
2
Flip-flops: 74HC74
a frequency divider — the lamps blink slower and slower
kh
HB-05
74HC74
Q0
Q1
Q2
Q3
IN
11×
OUT
5×
P
3×
N
3×
Hz
1×
Q
Q
1×
74HC04
1×
1
5×
4b
0
A
1×
∞
Ctrl
+
G
NAND3
74HC74
© 2026 Daniil Khanin · khanin.info · HB-05
21
CANVAS
1
Delete
0
ARM
0
DOOR
0
WIN
Reset
Reset
RESET
ALARM
READY
ALARM
880
2
Delete
74HC32
1A
DOOR
1B
WIN
2A
GND
2B
GND
3A
GND
3B
GND
4A
GND
4B
GND
1Y
OPEN
2Y
3Y
4Y
74HC08
1A
OPEN
1B
ARM
2A
GND
2B
GND
3A
GND
3B
GND
4A
GND
4B
GND
1Y
TRIP
2Y
3Y
4Y
© 2026 Daniil Khanin · khanin.info · HB-05
22
CANVAS …
3
Delete
74HC04
1A
TRIP
2A
RESET
3A
GND
4A
GND
5A
GND
6A
GND
1Y
nTRIP
2Y
nRESET
3Y
4Y
5Y
6Y
74HC00
1A
nTRIP
1B
ALQN
2A
nRESET
2B
ALARM
3A
GND
3B
GND
4A
GND
4B
GND
1Y
ALARM
2Y
ALQN
3Y
4Y
4
Delete
74HC02
1A
OPEN
1B
ALARM
2A
GND
2B
GND
3A
GND
3B
GND
4A
GND
4B
GND
1Y
READY
2Y
3Y
4Y
© 2026 Daniil Khanin · khanin.info · HB-05
23
NAND3
5
IN
3×
OUT
1×
P
3×
9×
A
B
C
Y
Y
VCC
G
P
A
Y
VCC
G
P
B
Y
VCC
G
P
C
6
N
3×
9×
Y
m1
G
N
A
m1
m2
G
N
B
m2
GND
G
N
C
7
Ctrl
+
G
Library
…
Chip N
2×
Library
…
NAND3
Enter
NAND3
A
B
C
Y
© 2026 Daniil Khanin · khanin.info · HB-05
24
74HC74
8
IN
8×
OUT
4×
1RD
1D
1CP
1SD
2SD
2CP
2D
2RD
1Q
1QN
2QN
2Q
9
NAND3
3×
12×
NAND3
A
1SD
B
1n4
C
1n2
Y
1n1
NAND3
A
1n1
B
1RD
C
1CP
Y
1n2
NAND3
A
1n2
B
1CP
C
1n4
Y
1n3
© 2026 Daniil Khanin · khanin.info · HB-05
25
74HC74 …
10
NAND3
3×
12×
NAND3
A
1n3
B
1RD
C
1D
Y
1n4
NAND3
A
1SD
B
1n2
C
1QN
Y
1Q
NAND3
A
1Q
B
1n3
C
1RD
Y
1QN
11
NAND3
3×
12×
NAND3
A
2SD
B
2n4
C
2n2
Y
2n1
NAND3
A
2n1
B
2RD
C
2CP
Y
2n2
NAND3
A
2n2
B
2CP
C
2n4
Y
2n3
© 2026 Daniil Khanin · khanin.info · HB-05
26
74HC74 …
12
NAND3
3×
12×
NAND3
A
2n3
B
2RD
C
2D
Y
2n4
NAND3
A
2SD
B
2n2
C
2QN
Y
2Q
NAND3
A
2Q
B
2n3
C
2RD
Y
2QN
13
Ctrl
+
G
Library
…
Chip N
2×
Library
…
74HC74
Enter
74HC74
1RD
1D
1CP
1SD
2SD
2CP
2D
2RD
1Q
1QN
2QN
2Q
© 2026 Daniil Khanin · khanin.info · HB-05
27
CANVAS
14
2
1Hz
2Hz
10Hz
60Hz
4kHz
…
MAX
15
Hz
1×
Q
Q
1×
2×
1Hz
CLK
Reset
Reset
CLR
16
74HC04
1×
1
7×
74HC04
1A
CLR
2A
GND
3A
GND
4A
GND
5A
GND
6A
GND
1Y
nCLR
2Y
3Y
4Y
5Y
6Y
17
74HC74
1×
12×
74HC74
1RD
nCLR
1D
Q0N
1CP
CLK
1SD
VCC
2SD
VCC
2CP
Q0N
2D
Q1N
2RD
nCLR
1Q
Q0
1QN
Q0N
2QN
Q1N
2Q
Q1
18
74HC74
1×
12×
74HC74
1RD
nCLR
1D
Q2N
1CP
Q1N
1SD
VCC
2SD
VCC
2CP
Q2N
2D
Q3N
2RD
nCLR
1Q
Q2
1QN
Q2N
2QN
Q3N
2Q
Q3
© 2026 Daniil Khanin · khanin.info · HB-05
28
CANVAS …
19
5×
5×
CLK
Q0
Q1
Q2
Q3
20
4b
0
A
1×
4b
0
Q
Q0
Q1
Q2
Q3
Q3 Q2 Q1 Q0 = 0101 → 5
© 2026 Daniil Khanin · khanin.info · HB-05
29
← Back to the lesson
Lesson 2. Flip-flops in a package: 74HC74 and a frequency divider