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AM503: Difference between revisions
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Regarding the AM503, Dale Dorando says: | Regarding the AM503, Dale Dorando says: | ||
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The AM503 was a redesign of the 6042 current probe from 1967. | The AM503 was a redesign of the [[P6042|6042]] current probe from 1967. | ||
It was initially going to be an oscilloscope plug-in. | It was initially going to be an oscilloscope plug-in. | ||
About 80% through the project design a new line of products was started called TM500. | About 80% through the project design a new line of products was started called TM500. | ||
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The AM503 was also intended to work with future higher frequency probes, like the P6022 with an added hall device for DC measurements. | The AM503 was also intended to work with future higher frequency probes, like the [[P6022]] with an added hall device for DC measurements. | ||
The smaller P6022 had a 120 MHz bandwidth, whereas the P6302 was only 50 MHz. | The smaller P6022 had a 120 MHz bandwidth, whereas the [[P6302]] was only 50 MHz. | ||
The design engineer (actually only an R&D technician) moved to the TM500 engineering and evaluation group before this probe was created. | The design engineer (actually only an R&D technician) moved to the TM500 engineering and evaluation group before this probe was created. | ||
The AM503 was being developed in the Accessories division in Beaverton, since that’s where the other current probes were designed. | The AM503 was being developed in the Accessories division in Beaverton, since that’s where the other current probes were designed. | ||
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There were some innovations that were incorporated in this design: | There were some innovations that were incorporated in this design: | ||
The cam switch with replaceable laser trimmed attenuator resistors, a 1GHz Gilbert cell op amp (actually developed by Howard Jones in 1963). | The [[cam switch]] with replaceable laser trimmed attenuator resistors, a 1GHz Gilbert cell op amp (actually developed by Howard Jones in 1963). | ||
This IC, 155-0078-xx, was being developed by Tek’s IC department. | This IC, [[155-0078-xx]], was being developed by Tek’s IC department. | ||
(At the same time these IC designers were teaching the technology at the University of Portland as part of Tek’s excellent education and training program.) | (At the same time these IC designers were teaching the technology at the University of Portland as part of Tek’s excellent education and training program.) | ||
The Peltola connector, developed by Tek’s Ron Peltola, a very low cost connector that worked well, even for the highest frequencies. | The [[Peltola connector]], developed by Tek’s Ron Peltola, a very low cost connector that worked well, even for the highest frequencies. | ||
A BNC was adapted to be used with the Peltola and is used on the front panel. | A BNC was adapted to be used with the Peltola and is used on the front panel. | ||
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The P6302 and P6303 probes utilized a Hall device that was manufactured in the clean room of the Accessories Manufacturing group. | The [[P6302]] and [[P6303]] probes utilized a Hall device that was manufactured in the clean room of the Accessories Manufacturing group. | ||
It was deposited onto a bar of ferrite that was later assembled into a U shape with other ferrite and potted in a mu-metal can along with the transformer bobbins. | It was deposited onto a bar of ferrite that was later assembled into a U shape with other ferrite and potted in a mu-metal can along with the transformer bobbins. | ||
The Hall device used for the DC measurements used a vacuum deposition process with indium antimonide. | The Hall device used for the DC measurements used a vacuum deposition process with indium antimonide. | ||
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The current probe would measure the current to ground through this resistor, so the voltage was near zero for the user. | The current probe would measure the current to ground through this resistor, so the voltage was near zero for the user. | ||
The 4KV supply was charged into a 4 ohm transmission line so a clean high current pulse would be generated. | The 4KV supply was charged into a 4 ohm transmission line so a clean high current pulse would be generated. | ||
This concept was taken from Tek’s 109 pulse generator. | This concept was taken from Tek’s [[109]] pulse generator. | ||
A trigger circuit was designed to fire the grid. It was based on the xenon flash circuit of the C5 camera flash, also in the Accessories group. | A trigger circuit was designed to fire the grid. It was based on the xenon flash circuit of the C5 camera flash, also in the Accessories group. | ||
The first prototype I made arced across the laser trim lines in the metal film resistor as they were cut perpendicular to the current flow. | The first prototype I made arced across the laser trim lines in the metal film resistor as they were cut perpendicular to the current flow. | ||
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Also interesting, the P6303 require special potting epoxy developed by 3M. The epoxy used in other current probes put excessive stress on the larger ferrite that caused the inductance to drop to zero. The magnetostriction property of ferrite. The epoxy could even also cause shear fractures in the ferrite. | Also interesting, the P6303 require special potting epoxy developed by 3M. | ||
The epoxy used in other current probes put excessive stress on the larger ferrite that caused the inductance to drop to zero. | |||
The magnetostriction property of ferrite. | |||
The epoxy could even also cause shear fractures in the ferrite. | |||
</blockquote> | </blockquote> | ||