To gather the devices for the new PCB there happened mistaken to order HC04. I wonder to be able to use HC04 as same as HCU04 and I checked operation on LTspice as below.
const int OUT_PIN = A3; //Changed for LCD Keypad Shield used
const int IN_PIN = A1; //Changed for LCD Keypad Shield used
//Capacitance between IN_PIN and Ground
//Stray capacitance is always present. Extra capacitance can be added to
//allow higher capacitance to be measured.
const float IN_STRAY_CAP_TO_GND = 24.48; //initially this was 30.00
const float IN_EXTRA_CAP_TO_GND = 2.0; // tuned
const float IN_CAP_TO_GND = IN_STRAY_CAP_TO_GND + IN_EXTRA_CAP_TO_GND;
const int MAX_ADC_VALUE = 1023;
//LCD Keypad Shield is used
LiquidCrystal lcd( 8, 9, 4, 5, 6, 7);
//digitalWrite(OUT_PIN, LOW); //This is the default state for outputs
Prior to use the bresd board, I checked the stray capacitance and inductsnce for the bread board clip terminals.
I used the 50ohm resister loaded jig for measuring the stray capacitance and inductance with nano VNA.
I connected nano VNA with the breadbosrd neighboring clipa. And I shorted on he other side of clips.
Within the bread board there are alligning a number of the clips as below.
It is the capacitance bedween the neighbour clips.
This time I would like to use a toroidal core for the trial making of an anntena . There are a number of cores in my junk box and I shall identify an adequate one from those. I used the Arduino LC meter and nano VNA to measure the inductance of coils used those cores.
The Arduino LC meter is good to measure the small coil inductance as several decade of nH. There is several error number by the jig and intrinsic circuit. However the gotten value is similar with gotten value by nanoVNA. The nano VNA is cooler than LCM because of measuring depending upon the frequency .
The result of this experiment I found #7（Estimated T25＃6） sample being suitable for my next trial.
There are the result of nano VNA meassured. S-parameter trasing shape may be dependent on its core material's nature.
Thia is bare coil.
This is the result for FB-101 ferrite core coil.
This is thr result for the carbonol iron dust core.
I'm trying LC meter of Franklin oscillator by Arduino. I had made PCB and assembled it. I estimated the cause of measuring instability.
Franklin oscillator is based on A-type amplifier on sharrow biassing unlike the Colpitts or Hartley oscillator. By LTspice simulation, .tran result reported slowly winding up of oscillation.
Accordingly, I reedited the sketch of Arduino to take some timing between parameter switching chances.
I will introduce how to operate the LC meter on YOUTUBE.
If you are interested in this circuit, you can purchase the bare PCB from PCBWAY as below.