TRANSISTOR CIRCUITRY IN THE LINCOLN TX-2 101

varied one at a time for most critical checking of the circuit. The following curves show the locus of failure points for various parameters as a function of the marginal checking voltage. Figure 11 shows the tolerance to tau, a measure of hole storage, and Figure 12 shows the tolerance to beta, the current gain. Operating mar gins for supply voltages, temperature, and pulse amplitude are shown in Figures 13 through 16.

The number of types of plug-in units was kept small for ease of production and to keep the number of spares to a minimum. The circuits are built on dip-soldered etched boards, and the components are hand soldered in solid turret lugs. The boards are mounted in steel shells shown in Figure 17 to keep the boards