AC128 Transistor Pinout, Equivalent, Features, Uses and Other Details

Today we are going to discuss about AC128 transistor pinout, equivalent, features, uses and other details about this PNP germanium transistor.


AC128 Transistor Pinout, Equivalent, Features, Uses and Other Details 


Features / Technical Specifications

  • Package Type: TO-1
  • Transistor Type: PNP
  • Max Collector Current(IC):  1A
  • Max Collector-Emitter Voltage (VCE):  32V
  • Max Collector-Base Voltage (VCB):  32V
  • Max Emitter-Base Voltage (VEBO):  10V
  • Max Collector Dissipation (Pc): 700 Milliwatt
  • Max Transition Frequency (fT): 1 MHz
  • Minimum & Maximum DC Current Gain (hFE): 55 – 175
  • Max Storage & Operating temperature Should Be: -55 to +75 Centigrade


NPN Complementary

NPN Complementary of AC128 is AC127


Replacement and Equivalent

Silicon material alternative for AC128 are 2N2905 , 2N4032, 2N3109, 2N3107, BC337.

Alternative for using in Fuzz Face are BC109, BC183, BC108, BC108C, CV7005, NKT275


AC128 Transistor Explained / Description

AC128 is a TO-1 package transistor. This is a germanium transistor which means that the material used in this transistor is germanium instead of silicon which is used in today’s transistors. AC128 transistor was introduced in 1960s and quite common in those days and used in many commercial devices such as radios, televisions, tape recorders, etc. but in comparison to today’s technology it is an old technology transistor. Nowadays technology has improved and more advanced transistors are invented and are constantly improving, therefore it cannot be used in modern electronic circuitry because the latest transistors performs way better than these older devices. But they are still used in some Fuzz Face devices for the guitar and perform better than the new silicon transistors and give a real feel because the Fuzz Face performance depends entirely on the transistors used in its circuits. So only the selected transistor works well in this device. The AC128 has been discontinued by its manufacturers but can still be found at some well-known electronics stores that stock up on old electronic components. But if you are not getting these transistors then you can also use the equivalent transistor mentioned above.


Where We Can Use it & How to Use

The AC128 transistor can be used in other circuits to replace other similar old transistors; the method of using these transistors is the same as we use any other PNP transistor.



Old Radios

Old Television Sets

Fuzz Face Circuits

Old Audio appliances


Safe Operating Guidelines / Absolute Maximum Ratings

To use this transistor safely, it is recommended not to use it at maximum rating and always stay below 20% as a safe aspect. The maximum collector current of the transistor is 1A so do not drive load of more than 800mA or 0.8A. The maximum collector to emitter voltage is 32V therefore do not drive load of more than 26V. Use a suitable heatsink with the transistor and always store or operate it in temperature above -55 °C and below +70 °C.



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