Please identify this old schematic symbol.

Ron H

Joined Apr 14, 2005
7,063
Those are NPNs with Schottky diodes from base to collector (diode anode to NPN base). The diode in this configuration is called a Baker clamp.
A saturated BJT has phenomenon called excess base charge. The transistor cannot be turned off until that charge is removed. A Baker clamp prevents deep saturation, reducing the amount of excess base charge. Baker clamps are used in circuits that need fast switching transistors.
 
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