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  1. Henneshoe

    how to get job in signal processing?

    I would start by applying for electronics technician jobs at engineering focused companies. I wouldn't worry about specializations right away. It is hard enough to find your first job after school without handicapping yourself by only looking at a subset of the job market. After landing your...
  2. Henneshoe

    CAN Bus Communications

    My understanding is most of the CAN in automotive is standardized by J1939.
  3. Henneshoe

    Flyback Converter Primary to Secondary Capacitor

    Thank you Comcokid and Grigson for your input. For clarification, we placed our capacitors on the "ground" of the secondary and the "ground" of the primary. Does 4.7nF seem like a reasonable value? We have more testing scheduled this week and as part of that we want to try larger and smaller...
  4. Henneshoe

    Quit a good job or not?

    Is it possible that your boss is un-aware of your frustration. If I was in your situation, I would let my boss know my ambitions. That being said, it seems the best way to move up the ladder is to look for a new job while you are employed. If a company is interested in you, it is one of the...
  5. Henneshoe

    Flyback Converter Primary to Secondary Capacitor

    Hi All, I am looking for a sanity check here. (And maybe a lesson in SMPS design.) I have a Flyback converter that was generating a lot of RF emissions. We placed a 4.7nF/500V capacitor between the primary and secondary windings and it greatly reduced the RF emissions (-15dB). I am a little...
  6. Henneshoe

    Stepping up Voltage

    For your final design I don't think the capacitor doubler will get you what you want. Your desired current is too high. Better to look at a Boost converter topology.
  7. Henneshoe

    Simple game for 2 to run over network.

    To setup the network communication you will need to learn socket programming. The network communication would be done through the winsock API. In VB.net the API is exposed through the System.Net.Sockets namespace. Tutorials for the technical details of using the interface can be found on...
  8. Henneshoe

    how to tackle this type

    The best suggestion I can offer is to brush up on your powers of persuasion. This sounds like a case where you are going to catch more flies with honey than vinegar. Try to become friends with this person. You will have a hard time trying to get someone to heed your advise if they do not trust...
  9. Henneshoe

    Discharging Cap causing problem in biasing of power amplifier.

    No problem, glad to help. I hope this is a good explanation of why you should add a voltage divider to the output pin of the pin driver. When the OE pin is pulled low is causes the output of the pin driver to tri-state. This means the output has a high impedance and isn't trying to pull the...
  10. Henneshoe

    Discharging Cap causing problem in biasing of power amplifier.

    The output is always enabled on the 7158 so the gate driver is pulled to ground. When the 1mhz pulse is off, the gate of the n-fet floats to 0V and the p-fet floats to 50V. Therefore, there is 0V across the n-fet gate capacitor and 50V across the p-fet capacitor. Once the first positive 1mhz...
  11. Henneshoe

    CE marking of low volage 1 to 5hp induction motors

    The LVD covers all electrical equipment (including electrical motors) operating in a range of 50 to 1000 Volts. If the air conditioner motor is rated within that range LVD is applied. Per the EC website (see link below): In respect of conformity assessment, there is no third party...
  12. Henneshoe

    Saving 2D drawing as ***.DWG

    I mostly work with circuit boards, but occasionally I need to look at or modify a 2D mechanical drawing from one of our Mechanical Engineers. They use AutoCAD, but I didn't want to buy a license for the few times I would use it. I use A9CAD (http://www.a9tech.com/). It is free and has most...
  13. Henneshoe

    GPS - RFID - International Communication - SMS not the preferred metho

    Is your GPS/RFID device a custom design or something you bought commercially? At a minimum I assume the cellular modem portion is a commercial device. In addition to talking with your cellular service provider you will need to check with the manufacturer of the cellular modem to see what...
  14. Henneshoe

    Schematics for a TENS

    If you place an RC Low Pass filter (with a cutoff frequency less than your PWM frequency) in the net named LOGIC3 then the base current of T1 would be controlled by your average voltage due to the PWM waveform and the resistor of the LPF. The collector current of T1 is then limited to base...
  15. Henneshoe

    Combine AC and DC signal (15A)

    I did a little looking, and a 30A transformer is actually a bit bigger and more expensive than I originally thought. Maybe it is worth looking into solid state.
  16. Henneshoe

    Combine AC and DC signal (15A)

    With the information given so far, I would look into using an isolation transformer. I think it would be smaller, cheaper, and simpler than a solid state circuit. See attached schematic.http://files.engineering.com/getfile.aspx?folder=204dcb08-bfef-47f3-91e0-f9c8cfac1d08&file=Schematic.JPG
  17. Henneshoe

    Common Mode Voltage of Thermocouple Input

    Thanks for the good reference. I guess I have some reading to do this weekend.
  18. Henneshoe

    Common Mode Voltage of Thermocouple Input

    I am specifying a 4 channel thermocouple device, and I am not sure what my requirements are for common mode range. I found some devices where each thermocouple is galvanicly isolated, so there is 500V common mode range. There are also devices where the thermocouples are not individually...
  19. Henneshoe

    PWM to control brushless 12VDC fan speed

    To expand on VE1BLL's idea. I assume during the dead-time of your PWM the fan voltage drops below 4.5V. This causes the integrated brushless DC motor controller to turn off. During the on-time, the motor controller powers up again, but not long enough to get the fan spinning. You could add a...
  20. Henneshoe

    Why not Ethernet vs. RS-485?

    Ethernet can run at multiple speeds (depending on what the hardware is capable of). By far, the most common speed for Ethernet today is 100 Mbit/s. At this speed Ethernet can use CAT5 or CAT6 cable. Commercial Ethernet cable is unshielded, but some industrial cable suppliers make a shielded...

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