The need for this testing setup arose while I was playing with making semiconductors from scratch. Specifically simple diodes from complete scratch. One being Cuprous Oxide, with interest in Aluminum Oxide as well.
While poking around with a graphite lead on the Copper Oxide layer, it quickly dawned on me that there was no really easy way to tell if I actually touched upon an active semiconducting layer. Probing a site with a multimeter and looking for some characteristics[what?] then swapping the leads to seeing if current is blocked in one direction, is one way, but slow and easier said than done. So I-V tracing got my attention.
What we need
- Material/Device under test
- Voltage and Current test rig
- Measuring device
- Function generator
What we have
Material/Device under test
Control Device: Silicon Diode
From the parts bin, tested with multimeter and/or LCR meter
Target Material: Copper Oxide
Home made semiconductor, see Cuprous Oxide – Copper(I) Oxide – Cu2O Diode
Voltage and Current Test Rig
Common configurations
Our choice setup
Measuring device
Two channels, both voltage in time domain
Oscilloscope
DSO vs CRT
Possibly Arduino
Function generator
Requirements:
* Sine wave
* Frequency: 20-100Hz1, let's say center frequency of 40Hz
555 Timer with square to sine wave circuitry
What I've tried:
* 555 with passive component low-pass filter
* Results in huge loss of voltage
Next steps:
* Still using the 555 as the oscillator, but using Op-Amps as an active filter.
* Specifically a cascade of integrator and low-pass filter
Links:
* Integrator/Low Pass Filter
* TI Bulletin
* Better "Explanation" of above three Op-Amp circuit
* Interesting Active band pass filter online calculator
