HISTORIC TRANSISTOR HOBBYIST SUPPLIES!
Supplies for the Transistor Historian and Kit Builder.
Only from the TransistorMuseum™
After the invention of the transistor
in the late 1940s, there was rapid development of new device types and
structures over the next two decades. One important goal was to produce transistors capable of high
frequency operation. Philco was an
early manufacturer of transistors, starting in 1953/54, with the famous
Surface Barrier Type (SBT). This
used a unique electrochemical etching process during manufacture that
allowed for an extremely thin germanium base layer, which in turn allowed
the transistor to operate at very high frequencies (20 to 30 MHZ). Philco sold millions of these
transistors in the 1950s, which were used in high speed digital computer
circuits and high frequency radio circuits. Improvements to the SBT technology lead to even higher
performing MAT and MADT transistors. This latter type, Micro Alloy Diffused Base Transistor, was introduced
by Philco in the late 1950s, and established the 2N501 as the “workhorse”
of high speed digital and switching applications. Several other transistor companies responded to this sales
success with second source versions of the 2N501, including Sprague,
General Transistor, General Instrument, CBS and ETCO.
Your MADT Transistor Order Will
be Supplied in the Storage/Display Envelope Shown Above, which Includes an
Insert with Historical Description and a Schematic.
2N501 MADT TRANSISTORS
Germanium PNP MADT
Micro Alloy Diffused Base
Transistor Type 2N501
1950s - 60s
Order Will Contain:
Tested 2N501 Germanium PNP
MADT High-Freq Transistors
the Style Shown Above)
Insert Depicting the Historical Importance of this Classic Transistor,
Includes a Schematic of an Early Transistor Digital Logic Circuit Using the
2N501 MADT Transistor
and Display Envelope
$10 per Package (Two Transistors)
Shipping Within U.S.
Determine Payments Options
COPYRIGHT © 2005
By Jack Ward