Breadboard Explanation and All
Components Connection List
Some builders have asked a question about how the
breadboard connections work underneath all the holes. On
the main central part of the board, each vertical column of five
holes is connected together underneath. Looking at the
matrix numbers on the bare board, in column 30 each of the five
holes a,b,c,d, and e are connected together. They are
connected to nothing else. Column 30 rows f,g,h,i, and j
are also connected together. They are connected to nothing
else. This is repeated for all columns 30 to 1.
At the top and bottom of the board there are the voltage supply
rails. These are labelled + and - on the top rails and +
and - on the bottom rails. All of the 25 holes on
the top + rail are connected together and to nothing else.
All the 25 holes on the top - rail are connected together and to
nothing else. The same is true for the two + and - rails
at the bottom of the board.
The matrix numbers and letters allow unique identification of
each hole on the main central part of the board.
Unfortunately they don't quite line up with the voltage rail
holes. I am going to uniquely identify the voltage rails
as as +TOP, -TOP, +BOT, -BOT with the holes going from 25 down
to 1 from left to right as I have built this unit. +TOP,25
would be the first + rail hole on the top left of the board
which is unused in this design. -BOT,1 would be the - rail
hole on the bottom right of the board which is used for a wire
link to -TOP, 1 in this design.
There follows a list of every connection and the associated
component. You can use this to resolve any ambiguity that
you might experience looking at the assembly photographs.
Where I have used pin numbers for the component legs, these are
assigned 1,2,3 left to right as seen in the component
description photographs linked in the bill of materials.
For example in the case of Q1, Pins 1,2,3 equate to C,E,B as
viewed from the front, the side with the writing on as seen in
the description photograph for Q1.
Wire links are referred to as SK.
In the case of polarised electrolytic capacitors pin 1 is the
+ve side and pin 2 is the -ve side with the white stripe.
In the case of diodes, pin 1 is the anode plain side and pin 2
is the cathode side with the back band.
Component Lead
Board Location
R1 Pin
1
26,j
R1 Pin
2
22,-BOT
R2 Pin
1
25,i
R2 Pin
2
21,+BOT
R3 Pin
1
22,j
R3 Pin
2
19,-BOT
R4 Pin
1
21,i
R4 Pin
2
18,+BOT
R5 Pin
1
18,j
R5 Pin
2
16,-BOT
R6 Pin
1
18,i
R6 Pin
2
15,+BOT
R7 Pin
1
17,i
R7 Pin
2
14,+BOT
R8 Pin
1
14,i
R8 Pin
2
11,i
R9 Pin
1
11,j
R9 Pin
2
9,-BOT
R10 Pin
1
11,f
R10 Pin
2
9,+TOP
R11 Pin
1
12,j
R11 Pin
2
10,-BOT
R12 Pin
1
3,f
R12 Pin
2
2,+TOP
R13 Pin
1
6,j
R13 Pin
2
3,j
R14 Pin
1
30,i
R14 Pin
2
27,i
R15 Pin
1
30,f
R15 Pin
2
23,f
R16 Pin
1
1,+TOP
R16 Pin
2
1,+BOT
C1 Pin
1
29,h
C1 Pin
2
27,h
C2 Pin
1
26,i
C2 Pin
2
23,-BOT
C3 Pin
1
25,h
C3 Pin
2
23,h
C4 Pin
1
22,i
C4 Pin
2
20,-BOT
C5 Pin
1
21,h
C5 Pin
2
18,h
C6 Pin
1
17,h
C6 Pin
2
12,-BOT
C7 Pin 1 +ve
15,j
C7 Pin 2 -ve
11,-BOT
C8 Pin
1
16,g
C8 Pin
2
14,g
C9 Pin
1
11,h
C9 Pin
2
10,h
C10 Pin 1 +ve
12,f
C10 Pin 2 -ve 10,-TOP
C11 Pin 1 +ve
5,h
C11 Pin 2 -ve 1,h
C12 Pin 1 +ve
24,+BOT
C12 Pin 2 -ve 24,-BOT
C13 Pin 1 +ve
5,+TOP
C13 Pin 2 -ve 5,-TOP
D1 Pin 1 +ve anode 3,i
D1 Pin 2 -ve cath 6,i
D2 Pin 1 +ve anode 6,h
D2 Pin 2 -ve cath 7,h
Q1 Pin 1
C
25,g
Q1 Pin 2
E
26,g
Q1 Pin 3
B 27,g
Q2 Pin 1
C
21,g
Q2 Pin 2
E
22,g
Q2 Pin 3
B 23,g
Q3 Pin 1
C
19,g
Q3 Pin 2
B
18,g
Q3 Pin 3
E 17,g
Q4 Pin 1
C
10,g
Q4 Pin 2
B
11,g
Q4 Pin 3
E 12,g
Q5 Pin 1
E
5,g
Q5 Pin 2
C
4,g
Q5 Pin 3
B 3,g
Q6 Pin 1
E
9,g
Q6 Pin 2
C
8,g
Q6 Pin 3
B 7,g
L1 Pin 1 Used only in modifications
L1 Pin 2 Used only in modifications
L1 Pin 3 Off board connection to VC1
L1 Pin 4 Off board connection to VC1
L1 Pin
5
29,j
L1 Pin
6
25,-BOT
J1 Pin 1 RED
28,b
J2 Pin 2 BLACK 25,-TOP
S1 Pin
1
26,a
S1 Pin
2
27,a
S3 Pin
3
28,a
VR1 Pin
1
15,a
VR1 Pin
2
16,a
VR1 Pin
3
17,a
LS1 Pin
1
1,j
LS1 Pin
2
3,-BOT
SK1 Pin
1
27,b
SK1 Pin
2
20,+TOP
SK2 Pin
1
30,g
SK2 Pin
2
15,i
SK3 Pin
1
19,j
SK3 Pin
2
17,-BOT
SK4 Pin
1
17,f
SK4 Pin
2
17,e
SK5 Pin
1
16,f
SK5 Pin
2
16,e
SK6 Pin
1
15,f
SK6 Pin
2
15,e
SK7 Pin
1
10,i
SK7 Pin
2
7,i
SK8 Pin
1
9,f
SK8 Pin
2
5,f
SK9 Pin
1
8,f
SK9 Pin
2
7,-TOP
SK10 Pin
1
4,f
SK10 Pin
2
3,+TOP
SK11 Pin
1
1,-BOT
SK11 Pin
2
1,-TOP
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© Henry J. Walmsley 2023
Recent edit history:
02-JUL-2025: Corrected title and description meta data