Search results

  1. C

    Create and output a waveform Vout=k*(t)^1/2 using Agilent 33250A

    Hi, I want to output a waveform Vout=k*(t)^1/2, k is a constant,t is time in sec. can I achieve this using Agilent 33250A? And how? Thanks.
  2. C

    How to use a Side-Brazed Dual In-Line Ceramic Package

    I have a silicon chip which has a built in capacitor pair. I use a Side-Brazed Dual In-Line Ceramic Package(shown below) to carry the chip. Wire bonding is used to connect the chip and package. http://www.spectrum-semi.com/CSB02810.pdf is the link to the package. I connect the package to an...
  3. C

    Drift issue in capacitance measurement, why?

    Hi everyone, Please be patient allowing me to introduce the problem shortly. I bought an evaluation board from a Japanese company recently. The board is used to measure very small capacitance difference by transfer input capacitance difference to output voltage, the resolution can reach 0.1fF...
  4. C

    Signal drifting/EM signal/Faraday cage/metal box with connector

    Hi, I am using a evaluation board to measure extreme small differential capacitance on the aF scale. I always got a drifting output, although the speed of drift is slow. I think this might due to the influence of environmental EM signal. I want to use a faraday cage to isolate the EM signal...
  5. C

    Where to solder electronic components on PCB in USA?

    Hi, I got a PCB and want to solder some electronic components on it. The components are very small, I want to find someone who can solder them for me. Is there such a company who are doing such business in America? Can anyone has experience telling me what I need to do?
  6. C

    amplifier gain not stable

    Hi, I found a differential amplifier board which was made several years ago. The gain of this differential amplifier is 213.765, but I made a simple measurement and found that the gain decrease as the input voltage increases. I wonder is this something normal? Does this ampilifer still...
  7. C

    What does this symbol mean

    Hi, I got a diagram of a capacitance readout chip like shown below. Could anyone please tell me what do those triangles with different numbers inside them mean? Thanks.
  8. C

    How is the wire routed on this evaluation board

    I am now working on designing an evaluation board for a capacitve read out chip since the board is no longer fabricated by the manufacture. The board is used to measure extremely small capacitance difference between external capacitors. The picture of the board is shown below. I am not sure...
  9. C

    Interesting wiring in designing an evaluation board for a capacitive readout sensor

    Hi, Please allow me to describe my situation first.I recently bought a capacitve readout sensor from a small Japanese company. Although this product is no longer manufactured several years ago, the company still has some inventory, so I could get some chip, but no evaluation board and no...
  10. C

    Need help on the evaluation board of a capacitive readout chip

    Hi, I recently bought a capacitive sensor readout from a Japanese company. They sent me an evaluation board diagram like following, I magnified the part in the red box. The corresponding evaluation board picture is as follows. The lower right corner corresponds to the part in the red box...
  11. C

    LQFP48 footprint

    Hi, I recently bought some chips packaged with LQFP48. The manufacture doesn't provide the footprint information. I wonder if the footprint dimension is same for all the LQFP48 packaged chip？ Thanks.
  12. C

    Question about layout of a PCB

    Hi all, I have a chip used to measure small capacitance(aF to pF). Below is its evaluation board. The area inside the red box is where I have question with. It is basically a connect lead used to connect to the capacitors being measured. A magnified version I have two questions: 1. Why...
  13. C

    How to purchase a electronic component oversea

    Hi I would like to buy an IC called AT-1006 manufactured by a Japanese company(ACT-LSI) which has no distributor in U.S. or Europe. I wonder is that possible that I entrust a electronic distributor in U.S. to purchase that for me? Has anyone done something similar before? Thanks.
  14. C

    Switch capacitor = low pass filter ?

    I understand that a switched-capacitor can be analog to a resistor with value R = 1/C*f, but I really don't see how can a switched-capacitor work as a low pass filter, could anyone give some explanation?
  15. C

    Which one has the lower noise level？Wheatstone bridge or direct measurement?

    Hi, In the Whetstone bridge circuit: If the circuit is balanced (and all resistances known), and we measure Vg as a function of time, then the fluctuations correspond to 4KbTR the well-known thermal fluctuations. My question:1.what should be used for R here? 2.And if...
  16. C

    Oscilloscope sampling rate

    Hi, I am using the Tektronix TDS 2024B oscilloscope, which has the maximum sample rate of 2GS/s. The manual also says it has a 2500 point record length for each channel. I know the sample rate is related to sec/div setting. I am interested in the actual sample rate with different sec/div...
  17. C

    interesting thing about oscilloscope at different SEC/DIV

    Hi, I use oscilloscope to measure a 1000Hz 6Vpp AC signal. I observed different traces shown on the oscilloscope screen which is interesting. When sec/div is 1ms, When sec/div is 5ms, When sec/div is 100ms, When sec/div is 250ms. When the sec/div is 50s, Observation: 1.As you can see...
  18. C

    question about ohm's law

    Hi, About Ohm's law, wikipedia has the following statement “Materials and components that obey Ohm's law are described as "ohmic" which means they produce the same value for resistance (R = V/I) regardless of the value of V or I which is applied and whether the applied voltage or current is DC...
  19. C

    What does the symbol mean?

    Hi, I have a function generator Agilent 33250A, On it output port, it has a symbol like shown below. What does it mean? The function generator has an inner circuit like , The shield is connected to the ground through a resistor and a capacitor, but I really don't see there is any relation...
  20. C

    Resistance of double sided adhesive conductive carbon tape

    Hi, Is anyone familiar with conductive tape? I thought conductive tape should have a resistance very small. And the supplier said it has a resistance of less than 5ohms/square. http://www.2spi.com/catalog/spec_prep/cond_adhes-tapes.shtml But I took a measurement today. I use a small part of...
Top