| Products > Test Equipment |
| Cheap SMD LCR Fixture, the Good, Bad and Ugly |
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| mawyatt:
--- Quote from: KungFuJosh on September 01, 2024, 04:13:45 pm ---I just measured your PCB, it looks like the $4 Adafruit 2459 should fit well. --- End quote --- We've got a few of those shown in your image, they were Ok but the one like we've shown performed better. Note how the plunger attaches to the Lever Arm frame. Maybe get few of each and try them out, they are really cheap. You need to mount the PCB on a BNC hosting fixture like shown. This was harvested from a cheap LCR Meter Kelvin Clip set also from AliEx. You want a rigid mechanical structure for the PCB to mount too. The PCB you have is an earlier version, doesn't have the "Guard" under the active DUT area, however that doesn't seem to matter much with lower Z measurements. Think we also sent you some of the very early version PCBs (can't remember) which have the 4 BNCs directly mounted to the PCB, these worked well but we wanted a more rigid mechanical structure and prefer the latter version as shown. Get yourself some low Z High Precision SMDs for checking things out, 2512 Resistors are a good start, and relatively easy to handle being large. Best, |
| KungFuJosh:
--- Quote from: mawyatt on September 01, 2024, 11:51:16 pm ---We've got a few of those shown in your image, they were Ok but the one like we've shown performed better. Note how the plunger attaches to the Lever Arm frame. Maybe get few of each and try them out, they are really cheap. --- End quote --- Do you have any links to stuff you liked? --- Quote from: mawyatt on September 01, 2024, 11:51:16 pm ---Get yourself some low Z High Precision SMDs for checking things out, 2512 Resistors are a good start, and relatively easy to handle being large. --- End quote --- I love 2512 resistors. That's what I usually use on my SMT guitar amp PCBs. Much less likely to go flying when I check them with a tweezers, and much easier to find when they do. 😉 |
| mawyatt:
--- Quote from: KungFuJosh on September 02, 2024, 12:27:18 am --- Do you have any links to stuff you liked? --- End quote --- Cheap Kelvin Clips for LCR Meter, toss everything except the case and BNCs, which we used. https://www.aliexpress.us/item/3256804400699838.html?spm=a2g0o.order_list.order_list_main.90.503618020zePkv&gatewayAdapt=glo2usa Preferred type Lever Arm & Plunger. https://www.aliexpress.us/item/3256803387853373.html?spm=a2g0o.order_list.order_list_main.149.503618020zePkv&gatewayAdapt=glo2usa Different type. https://www.aliexpress.us/item/3256801104879812.html?spm=a2g0o.order_list.order_list_main.255.503618020zePkv&gatewayAdapt=glo2usa You need to get a few of the plungers and go through them to find the better ones, being so cheap they are highly variable!! Try out both types, they both work, we just like the version shown slightly better. Be sure and use an internal shield with the BNC case, especially if you don't use shielded wires to the PCB (like we did originally). We made one up with the shielded wires for higher frequency use, however the unshielded wires worked fine, OCD ;) Note how you can flip over the plunger to use the standard supplied tip (black) for larger SDM DUTs. Best, |
| KungFuJosh:
Thanks! Your second link is the same as the first though. |
| mawyatt:
Fixed now!! Best, |
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