Point Contact Transistor Separation Pressure Spec 1948
# 1948 Refinement — Set Their Separation and Pressure Carefully: The Number This Series Referenced but Never Stated
Point spacing has been a load-bearing phrase in this series since its very first step. Step 1 argued diffusion length has to exceed it. Step 3 ground a contact face to a roughness standard set by it. Steps 11 through 13 built, positioned, and measured two independent point contacts against it. None of those steps ever stated what the actual distance was, because each one only needed to establish that some specific distance mattered, not what that distance should be in absolute terms. This refinement, documented alongside the two-wire construction in the previous step, is where the patent finally reports a number: good results with separation of 1 to 10 mils, roughly 25 to 250 micrometers.
The patent reports a range rather than a single value, and that range is consistent with this series' own argument rather than a departure from it. Since Step 1, this project has insisted that no spacing or roughness standard is correct in general — only correct relative to the specific device's diffusion length, point sharpness, and germanium condition. A single fixed number for every device would contradict that argument directly. A reported range of good results says the same thing the earlier steps said in the abstract: the right value depends on the specific points, the specific germanium, and the specific forming result, and 1 to 10 mils is the window within which devices built to this construction's other specifications tend to actually work, not a universal constant every device must hit exactly.
Pressure is the second quantity this step names, and it closes a loop Step 12 opened without a number. Step 12 argued that spring tension had to be bounded on both sides — too little for a reliable contact, too much for the germanium or the formed alloy region — but specified neither bound numerically, because the correct tension depends on the specific spring, point, and germanium body involved. This refinement does not supply a universal number for pressure either, but it places pressure in the same sentence as separation, treating the two as a matched pair that has to be set together rather than independently — a separation chosen correctly with the wrong pressure, or a pressure chosen correctly at the wrong separation, is not obviously better than getting both wrong, because the two quantities interact in how reliably the device actually performs.
| Step | Process operation | Input | Output | Specification | Constraint |
|---|---|---|---|---|---|
| 24.1 | Set the point separation within the reported 1 to 10 mil range, consistent with Step 13's own positioning procedure | Two-wire construction from the previous refinement, Step 13's positioning method | Separation within the documented range | Measured separation between 1 and 10 mils, roughly 25 to 250 micrometers | A separation outside this reported range has no documented basis for good results, even if it technically satisfies Step 1's diffusion-length comparison |
| 24.2 | Set the spring pressure for each point jointly with the separation chosen in 24.1, not independently | Separation from 24.1, spring construction from Step 11 | Jointly set separation and pressure | Pressure chosen with reference to the specific separation value, not set by a fixed target applied regardless of spacing | Setting pressure without reference to the actual separation can produce a combination that performs poorly even though each value looks acceptable alone |
| 24.3 | Verify device performance against the combination actually used, not against separation and pressure checked in isolation | Jointly set values from 24.2 | Performance-verified device | Measured electrical characteristics consistent with "good results," the patent's own stated outcome for this combination | Verifying separation and pressure as two independent checks can pass a combination the patent's own reported range would not have endorsed |
| 24.4 | Record the specific separation and pressure values used against the device's complete record | Verified device from 24.3 | Documented separation-and-pressure configuration | Values recorded against every provenance record since Step 2.6 and the construction method from the previous refinement | Without this record, a later device's performance cannot be compared against this one's specific, documented operating point |
This refinement does not introduce a new requirement; it finally reports the number every earlier requirement was written around. Step 1 through Step 13 built an entire argument about point spacing without ever needing to state what the spacing actually was, because each of those steps only had to establish that the device's own geometry set the standard. This is the step where that standard gets an actual value attached to it, reported not as a single correct number but as the range within which this specific construction — two independent wires, placed and seated the way Steps 10 through 13 already described — was found to work.