Recent content by BlackPowder

What is the difference between those horns/waveguides and regular metal pieces with a same geometry? Why the microwave companies sell those parts at hundreds and thousands dollars? Why we cannot buy some metal sheets or pipes on McMaster-Carr with very low price and make some microwave...

This is amazing. I won't go to atmega328 if attiny works. Thank you for the advice.

This is a very nice piece. Thank you. But unfortunately, like what Rive said on #10, the sensor chip I am using doesn't support hot-swapping. I have to think about this carefully.

Thank you for the advice. I always have a backup plan of moving the sensor by servomotor to sweep over the sample if "sensor array" is a dead-end.

Yes. Analog switches are what I am searching right now.

I am trying to control a massive amount of electrodes (position-fixed leads of a capacitance sensor FDC2214 for imaging, more electrodes means higher resolution). The control here is merely a "connected/disconnected" from each electrode to FDC2214. What kind of relay or switch is not yet...

Thank you for the advice. You are right, an IO expander really helps here. Also, I just found a switch array chip MT8809, but I am not sure if those internal switches could interfere with each other.

Is there any solutions for a micro controller to control massive amount of relays, such as 100 of them? Do I really need 100 I/O ports for this circuit? I can make one master MCU with couple slaves to get many I/O ports. But I think there must be some better way to do it.

There is a type of ionization called "Penning Ionization" that an excited species which at an energy level higher than the ionization threshold of another species can ionize that species during collision. In the mixture of He and N2, the Penning ionization is He* + N2 => He + N2 + e. This is...

Thank you for the reply. I have moved a step forward about this problem. Here is something funny. The attached figure shows the results of the Boltzmann solver solving for Townsend coefficient and e-impact ionization rate coefficient of He and N2 under different mix ratio. For the Townsend...

Thanks for the reply. My trouble is to find the degeneracy of N2(C3∏u) and the degeneracy of N2+(B2Σg+). So far, according to the literature [1], the degeneracy is a product of electron spin statistical weight, vibrational statistical weight, and rotational statistical weight. According to...

I am trying to calculate the electron temperature using optical emission spectrum intensity ratio. The equation includes degeneracy values of N2(C3πu) and N2+(B2Σg+). I have found the way to get the degeneracy of N2(C), but not sure if I can do the same thing to the excited ion N2+(B).

The calculation of degeneracy of diatomic molecules can be easily found. However, there is no detail introduction of ions. Not sure if the electronic, vibrational, rotational, and nuclear spin statistical weights are differ from N2+ to N2. Please help. Thanks.

Helium has a higher 1st ionization energy (24.58eV) than N2 (15.6eV) and O2 (12.06eV). For an atmospheric room-temperature helium, why it is easier to get ionized than the daily life air under a same discharge setup? For example, for the Paschen curves, N2 locates at the left of He which means...

Hi, I am new on PF. I am a PhD student in the George Washington University. I mainly focus on low temperature plasma jet.