Products > Test Equipment
Show Us Your Curve Tracer
FrancisM:
Here's my own one, designed for small signal transistors. I got the idea from an old Elektor article.
It can show output characteristics and transconductance curve of jfets or mosfets.
The sweep is an adjustable triangular wave of +-14V max, the current limit can be set to 25mA or 250mA. Done with a TL074.
The base (gate) is voltage driven by a pic18F1320 and a double buffered dac MCP4822. I select the base resistor with jumpers.
Having a single bipolar supply, the current is monitored across a 0.1 Ohm shunt in the emitter (source). It's then amplified 100x by an AD797 to the Y output. I can change triangular's wave frequency to get rid of the looping effect with highly capacitive transistors.
The result is not that bad on newer DSOs, no flickering at all with the right setup, but still not such a nice trace as with my TEK 2465B.
Things may probably change in the next coming years with affordable high definition scopes.
The first screenshot is from an NPN ZTX851, little transistor with big die. It behaves nicely at low Vce. I don't like the colour but can't change it.
The second one is the transconductance curve from an N chanel PF5102. It was first in the fridge, then on the setup and heated with an air gun. With persistence, one can see the sweet spot of it's zero tempco.
I also own a USB Locky_Z one. I got it many years ago at the first run for cheap. It's fully made of used parts and was first released for the chinese market. But it still works.
Francis
Martin Hodge:
A Tek 575 connected to an Eico 667 tube tester through a custom curve tracer circuit.
Curves are from a 6AU6 pentode.
graybeard:
--- Quote from: Martin Hodge on March 09, 2021, 07:03:53 am ---A Tek 575 connected to an Eico 667 tube tester through a custom curve tracer circuit.
Curves are from a 6AU6 pentode.
--- End quote ---
I have been considering how to adapt tubes to my 575. Thank you for this example!
Jay_Diddy_B:
Hi group,
I have a few. I have a Huntron 2000 for troubleshooting.
Tektronix 576 for looking at transistors and diodes.
Tektronix 571
My best curve tracer is an HP 4155B Semiconductor Parameter Analyzer:
This picture is Id and GM versus Vgs for 2N7002 MOSFET.
The vertical scale (Id) is logarithmic and goes from 1fA (1E-15) to 100mA (1E-1) 14 decades :D
Regards,
Jay_Diddy_B
Electro Fan:
--- Quote from: Jay_Diddy_B on March 10, 2021, 03:39:19 am ---Hi group,
I have a few. I have a Huntron 2000 for troubleshooting.
Tektronix 576 for looking at transistors and diodes.
Tektronix 571
My best curve tracer is an HP 4155B Semiconductor Parameter Analyzer:
(Attachment Link)
This picture is Id and GM versus Vgs for 2N7002 MOSFET.
The vertical scale (Id) is logarithmic and goes from 1fA (1E-15) to 100mA (1E-1) 14 decades :D
Regards,
Jay_Diddy_B
--- End quote ---
14 decades to a femtoamp?! Very neat!
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version