Author Topic: TeensyLCR – A Teensy based DIY LCR Meter  (Read 53665 times)

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Offline HaiLun

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Re: TeensyLCR – A Teensy based DIY LCR Meter
« Reply #50 on: January 24, 2025, 12:49:49 am »
Very nice project. 

I'd like to add a good transistor hFE tester to this.  Something that could test with base current > 1.0 uA, VCE > 1 volt and read betas higher than ~600.  These are the parameters of most of the current transistor testers.

It would be great if it had a thermistor attached to the transistor and it measured hFE at different temperatures as the transistor heated up.
 

VCE > 1   ………… Are you sure 1V is enough?
 

Offline drksy

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Re: TeensyLCR – A Teensy based DIY LCR Meter
« Reply #51 on: January 24, 2025, 02:24:10 am »
What's the total cost to build one from scratch, only counting the electronics, no enclosure, no kelvin alligators or other mechanical/misc stuff?
 

Offline WeTecTopic starter

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Re: TeensyLCR – A Teensy based DIY LCR Meter
« Reply #52 on: January 24, 2025, 02:13:41 pm »
I'd like to add a good transistor hFE tester to this.  Something that could test with base current > 1.0 uA, VCE > 1 volt and read betas higher than ~600.  These are the parameters of most of the current transistor testers.

I had the idea to add a DC output like Agilent E4980A option 001. This can also be used to measure RDSon of MOSFETs. A DAC module could easely be implemented. I had this in mind: DFRobot GP8211 1-Channel 15-bit I2C to 0-5V/10V DAC Module (https://www.dfrobot.com/product-2753.html).
 

Offline WeTecTopic starter

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Re: TeensyLCR – A Teensy based DIY LCR Meter
« Reply #53 on: January 24, 2025, 04:43:41 pm »
What's the total cost to build one from scratch, only counting the electronics, no enclosure, no kelvin alligators or other mechanical/misc stuff?

  • PCB with most of the passives preassembled: 80$ (incl. shipping+taxes) for 5 pcs.
  • Display: 10$
  • Teensy 4.1: 32$ (was a christmas pressent, so 0$ for me)
  • Most of the ICs where salvaged from other PCBs or samples. So 0$ for me. About 87$ at Digikey for 1 unit.
  • BNC connectors: 16$ (Salvaged from other PCBs, so 0$ for me.)
  • Cheapo 4x4 keypad: 1$. I used a selfmade keyboard PCB: 7$ for 5 pcs.
  • rotary encoder: 2$

I paid about 100$. In addition to the fun of building it, it was absolutely worth it. If you are going to build it from scratch it will cost about 235$ + additional cost for kelvin alligators clips and other stuff. Depends what is laying around and in the junk box.  ;D
 
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