Component replacements for my electronics projects

Some people living outside Europe might have problems in getting those components types which are very widely used in Europe. If you happen to have this problem then read further. This document tries to give information how to find suitable replacements to be used in my projects.

Replacing transistors

My electronics project are not generally very sensitive to exact component types used, so the trasistors can quite freely changed to some other transitor with similar specifications.

NPN transistors

The general purpose transistor I use is BC547. It is a very common general purpose transistor in European electronics circuits and has following characteristics:

Voltage rating: 50V
Maximum current: 0.1A
Power rating: 0.5W
Frequency range: 300 MHz
You can try to replace that transistor with quite many general purpose trnasistors with similar specifications without much problems. A quite suitable replacement for many projects could be 2N2222 and 2N3904 universal NPN transistors. They have the following specs:
                  2N3904        2N2222

Voltage rating:    60 V         60..75V
Maximum current:   0.1 A        0.8 A
Power rating:      0.625 W      0.5 W
Frequency range:   >250 MHz      >250 MHz
Amplification (B): >100          >100
(it has different pinout and can handle more power but is otherwise quite similar to BC547).

PNP transistors

The PNP transistor type I commonly use is BC557. It has following specs:

Voltage rating: 50 V Maximum current: 0.1 A Power rating: 0.5 W Frequency range: 150 MHz

You can try to replace BC557 with 2N3905 transistor which has the following specs:

Voltage rating:    40 V
Maximum current:   0.2 A
Power rating:      0.625 W
Frequency range:   >200 MHz
Amplification (B): >50
Or you can use 2N3906 which has similar characteristics, but the amplification is >100.

Replacing diodes

The most typical diodes I use are 1N4148 and 1N4001. 1N4148 is very common small signal diode which sould be easy to get almost everywhere. 1N4148 has the following specs:

Diode type:      Fast switching diode
Voltage rating:  100 V
Current rating:  0.2 A
Swithing time:   < 4 ns
If you can't get exactly this model you can try to replace 1N4148 with 1N914 or 1N4448.

1N4001 is a very common rectifying diode with the following specs:

Diode type:      Rectifying, general purpose
Voltage rating:  100 V
Current rating:  1 A
You can replace 1N4001 with almost any general purpose rectifying diode with similar or better specifications.

In some circuits where 100V voltage rating is not ehough, I use 1N4007 diode. 1N4007 is the same as 1N4001, but has 1000 V voltage rating.

Tomi Engdahl <>