P6042
The Tektronix P6042 is a DC to 50 MHz current probe introduced in 1967. It was designed by Cal Hongel.
The sensor contains a current transformer for HF and a hall effect sensor for LF/DC components. The amplifier combines DC/LF and HF signals.
The AM503, introduced about a decade later, is a redesign of the P6042 with removable probes.
Key Specifications
| Bandwidth | DC to 50 MHz (−3 dB) |
|---|---|
| Rise time | 7 ns |
| Ranges | 1 mA/div to 1 A/div (1–2–5) |
| Output | to 50 Ω scope input at 50 mV/div |
| Maximum input | 10 A DC+peak AC in 5 mA to 1 A ranges, 0.5 A in 1 mA and 2 mA ranges |
| Power | 90-136 or 180-272 V, 20 W |
Links
- Tek P6042 page @ amplifier.cd
- Tek P6042 page @ barrytech.com (waybackarchive)
- Tek P6042 page @ radiomuseum.org
- P6042 repair by Fred, PA4TIM
- P6042 teardown @ EEtimes
Documents referencing P6042
| Document | Class | Title | Authors | Year | Links |
|---|---|---|---|---|---|
| Service Scope 46 Oct 1967.pdf | Article | P6042 DC-to-50 MHz Current Probe | Cal Hongel | 1967 | P6042 |
| Tekscope 1973 V5 N1 Jan 1973.pdf | Article | Repairing Oscilloscope Probes | 1973 | P6006 • P6021 • P6022 • P6042 | |
| Tekscope 1974 V6 N3.pdf | Article | Using your oscilloscope probe (Part 2) | Riley Stock | 1974 | P6201 • P6042 |
Patents that may apply to P6042
| Page | Title | Inventors | Filing date | Grant date | Links |
|---|---|---|---|---|---|
| Patent US 3453403A | Power selection device | Eldon Hoffman | 1966-08-18 | 1969-07-01 | 115 • 140 • 141 • 141A • 144 • 145 • 146 • 147 • 148 • 149 • 149A • 230 • 284 • 286 • 453 • 454 • 491 • 520A • 521A • 522 • 545B • 547 • 556 • 561B • 564B • 568 • 576 • 611 • 647A • 1340 • 2101 • 2601 • 4501 • 5030 • R5030 • 5031 • R5031 • P6042 • P7001 • 7503 • 7504 • 7704 • 7704A • 7904 • R7903 |
| Patent US 3482163A | Magnetic signal measuring device including degaussing means | Bill Peek • Eldon Lee Hoven | 1967-05-24 | 1969-12-02 | P6042 • A6302 • A6302XL • A6303 • A6303XL • A6304XL • A6312 • AM503 • AM503A • AM503B • AM5030 • 11A16 |
Prices
| Year | Catalog price | In 2026 dollars |
|---|---|---|
| 1967 | $525 | ~$5,200 |
Internals
Locking the probe requires pushing past the resistance felt when the core almost closes. This engages a mechanism that firmly presses both core halves together, and extinguishes the "Probe unlocked" indicator.
The P6042's core halves are precision lapped and potted with epoxy. They have Mu-metal screening. The lower (fixed) core also contains the Hall element. According to Dale Dorando, who designed the AM503, the Hall device was probably made with indium antimonide (InSb).
Unfortunately, the P6042 probe is quite sensitive mechanically, and in many units offered for sale, the cores are damaged.
The amplifier front-end is constructed using a 156-0014-00 differential amplifier integrated circuit, labelled "M18", which cross-references to a long-obsolete Teledyne "831-BE". Jim Williams' Application Note 61 contains a replacement circuit using LT1228 opamps (page 19).
Pictures
-
amplifier front
-
amplifier and sensor
-
sensor detail
-
rear view
-
catalog image
-
P6042 amplifier internal view
-
P6042 amplifier internal view
-
P6042 amplifier internal view
-
Top half core of probe
-
Bottom of probe with half core and Hall sensor
Components
Some Parts Used in the P6042
| Part | Part Number(s) | Class | Description | Used in |
|---|---|---|---|---|
| 156-0014-00 | 156-0014-00 | Monolithic integrated circuit | amplifier | P6042 |
