UBM Tech
UBM Tech

Shyam Sunder Tiwari

's profile
Managing Director

I live in this small city Gwalior, MP, India. I am a Physicist by education, Nuclear Scientist by Training, Electronics and Software professional by work. I am right now planning sensors and monitoring systems for water resource management and also developing technology to kill Pathogen in water / fluids by nano-second high voltage discharge pulses. Good quality drinking water is my primary concern right now. Some of our current work can be seen at


's contributions
  • 08.15.2013
  • How to select precision resistors for 4–20 mA current loop
  • Yuval Hernik, Points are well taken and 4-20mA look sure has some serious consideration if wires run too long or likely to be subjected to ESD of 25kV. There is some smell of Vishay products publicity in it but I think that is all right as long as it serves a purpose. Dr. Shyam
  • 08.07.2013
  • LTC nano-power buck-boost DC/DC
  • I think it is a good development but I dislike those tiny packages and prefer some working spaces like SOIC / DIP etc..
  • 08.08.2013
  • Dual, low-noise JFET has low capacitance and high input impedance
  • I agree that Linear Systems has done a great contribution in not only developing the replacement JFETs but also their own better specifications. I want to try these parts myself. I have tried their other now noise low current parts also and improvement in input capacitance is good one for high frequency applications. 4pF is just great. Dr. Shyam
  • 06.28.2013
  • Detect charged bodies with electronic electroscope
  • This circuit perhaps can be used to test differential charge stored on a capacitor if capacitor has 1nF and above value and voltage on capacitor is sufficient enough to trigger the 4011 IC Gate (2X threshold). As there is no protection, extra voltage may damagee the 3011 IC Gate. Normally C1 will remain charged and C2 fully dischrged. Condition is to be reversed to see any change in the output. Perhaps this circuit can capture static charge from free ions in air and then it can reflect in the output. If large area charge collector plates are connected to electrodes then it will easier to collect charge. 10M+10M impedance with 100pF capacitor likely to see input as open circuit and can pick up EM from power lines and output may flicker randomly. Movement of people or hands around circuit may also trigger. This design is not proper.
  • 05.20.2013
  • Sodium power cables
  • Another variant is a Hot Liquid Sodium Metal Cables which can flow itself within the cable (pipe) and can be pumped out if you don't need it anymore. Of course when Sodium cools down due to power failure then you will see what you are discussing here. Advantage is that Sodium metal is a good heat conductor and and is used as coolant in Fast Breeder Reactor. Now you can use for typical electric current paths also if you think it will fit into your high temperature Batteries or anything of that kind.
  • 06.10.2013
  • Frequency threshold detector
  • It is difficult to define capacitor's properties in software simulation and there comes a major problem in timing devices. I understand that most of the teacher will love such designs as they are easy for the classroom testing but those are in industry clearly avoid them. Do you measure frequency by counting pulses or do you convert frequency to voltage and then measure voltage as frequency value. Frequency to voltage uses charge averaging from mono-stable pulses and result is not very accurate. However permits frequency discrimination. LM2907 /LM2917 can be used for frequency discrimination if you like simple analog designs like tachometer alarm etc.