Vintage Radio


Transistor Markings
Repairing Old Radios
 
 

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Transistor Equivalents
for the substitution of modern transistors in elderly projects

The links at left may help you to research your own replacement transistors. Should you find any info that can fill in any of the blanks in the matrix below... Please Email the details so that I can update them in and thus help everyone else.

This page was stalled, pending the finding of more complete data, but an English gent, George Hurley, now living in New Zealand, has provided all the missing information... Thanks.

The Apidictor was designed in the early 1950s and contained three types of transistor, each of which could be of two specified types, but none of these are in general supply as of the early 2000's.

Schematic
ref.
Original
transistor type
Original
alternative type
Modern
Substitute
Alternative
Substitute
tr1 or tr2OC 202OC 7022N 1475BCY 32
tr3 or tr4AC 107NKT 226AC 107N
tr5 to tr11OC 71NKT 2242N 406AC 1077

Parameter chart

TypeCaseNPN
or
PNP
MatLVce
V
Vcb
V
Veb
max
V
Ic
mA
Hfe
min
Hfe
typ
Hfe
max
Ic
@
Hfe
mA
ft
MHz
Ic
@
ft
mA
Ptot
mW
Tjunc
C
max
Use
AC107TO1PGe1515101030-16032380L.N. Audio
OC71TO1PGe1030105030-7556<112580Audio GP
OC202TO1PGe1510105040--11-250150-
NKT 224TO5PGe30101050030--10.5-30085-
NKT 226TO5PGe30101050050--10.5-30085-

There are still a few gaps, but there is enough information in these tables to be able to compare modern transistor specifications, so that these old items can be kept functioning.

Written... 22 April 2004, Upgraded... 03 May 2005,
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