Core Drivers - Model V and Model VI Applications, Limitations, and Modifications, 1954 March 20

MIT DIC 6889. Project Whirlwind Memo M-2764. A transistorized core driver, employing one point-contact and one junction transistor, which can drive the equivalent of about 200 metallic magnetic memory cores in series is discussed in detail. A current output of 12 ma with a rise time of 0.3 µsec can be obtained from this circuit. The note begins with a discussion of the relative merits of point-contact and junction type transistors as core drivers. This is followed by an analysis of the grounded-emitter connection of the junction transistor. Next, the transistorized core driver circuit is presented and discussed in detail, including input and output characteristics, design criteria, and voltage margins. Finally the current and voltage outputs from the driver when it is driving the equivalent of a memory plane are shown. The note terminates with a paragraph on the future prospects for this type of driver.