HC14 Hex Schmitt Trigger Inverter Study Notes - Part 1

HC14 Hex Schmitt Trigger Inverter Study Notes - Part 1

I searched my components box and found a couple of HC14.  I also unexpectedly found two DAC0806 which have been hiding there for years, collecting dust.  I wonder if I can use them for my tunnel diode tests.

I remember I have written some posts on HC14 in the rpi.org.forum.  So I found it just now and pasted the links for reference.

Old Schmitt Trigger Post 1 - rpi.org.forum.

Old Schmitt Trigger Post 2 - rpi.org.forum.

Old Schmitt Trigger Post 3 - rpi.org.forum.

Triangular Wave Sig Gen Evaluation - Part 1

Triangular Wave Sig Gen Evaluation - Part 1

The ICL8038 sig gen performance is disappointing, mainly because the signal is not too stable, therefore difficult for the scope to sync.

So I tried to use two NE555 timer, hoping to generate square wave and then use a RC low pass filter to convert square wave to sine wave.  However, I found the cheapest 555 timer has a very limited frequency range, and the better 555 timer difficult to set desired frequency and duty cycle.

In other words, all three sig gen tried are not that usable.  So I decided to tried the Schmitt trigger oscillator.

Schmitt Trigger Oscillator

How to Design Schmitt Trigger Oscillators - Eduardo Corpeño 2018may24

Exactly How Schmitt Trigger Oscillators Work - Eduardo Corpeño 2018may23

How to Design Schmitt Trigger Oscillators - Eduardo Corpeño 2018may24

Tunnel Diode I-V Curve Plotting Chat Selfie Walkthrough

Tunnel Diode I-V Curve Plotting Chat Selfie Walkthrough

    Step 1  

   

Step 2 - Circuit Fantasist's setup

Step 3

Step 5

Step 6

Step 7 - Triangular Wave to use and Tektronix Curve Tracing Results

Step 8 - AD5933 Impedance Converter to measure tunnel diode resistance and inductance (also for bio sensor for a side project)

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ICL8038 Datasheet Summary

 ICL8038 Datasheet Summary

ICL8038 Precision Waveform Generator/Voltage Controlled Oscillator

The ICL8038 waveform generator is a monolithic integrated circuit capable of producing high accuracy sine, square, triangular, sawtooth and pulse waveforms with a minimum of external components. 

The frequency (or repetition rate) can be selected externally from 0.001Hz to more than 300kHz using either resistors or capacitors, and frequency modulation and sweeping can be accomplished with an external voltage. 

The ICL8038 is fabricated with advanced monolithic technology, using Schottky barrier diodes and thin film resistors, and the output is stable over a wide range of temperature and supply variations. 

These devices may be interfaced with phase locked loop circuitry to reduce temperature drift to less than 250ppm/oC.

Features

* Low Frequency Drift with Temperature. . . . . . .250ppm/oC

* Low Distortion. . . . . . . . . . . . . . . . 1% (Sine Wave Output)

* High Linearity . . . . . . . . . . . 0.1% (Triangle Wave Output)

* Wide Frequency Range . . . . . . . . . . . 0.001Hz to 300kHz

* Variable Duty Cycle . . . . . . . . . . . . . . . . . . . . . 2% to 98%

* High Level Outputs . . . . . . . . . . . . . . . . . . . . . . TTL to 28V

* Simultaneous Sine, Square, and Triangle Wave

Outputs

* Easy to Use - Just a Handful of External Components Required

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Tunnel Diode Twilight Zone Problem

 Tunnel Diode Twilight Zone Problem

GE TD 62 User Guide explain why I could not draw the I-V curve in the NDR region, and how I can do that. 

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AD5933 Module Setting Up Notes

AD5933 Module Setting Up Notes

I have set up the module and Rpi with the TSB0104 logical level converter can "i2cdetect -y 1" it OK.  Next step is to measure simple resistance and inductance, and hopefully, finally the tunnel diode negative resistance and inductance..

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