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  1. CDRIVE

    will a basic buffer be sufficient?

    Adam, I suspect we may need more than one brain helping here. ;) For instance; we don't know if he's intending to use a single ended (Vcc,Vdd) or bipolar OpAmp. If it's going to be a single ended model what would be his best choice, with good 0V output offset? Sadly, I've not kept current and...
  2. CDRIVE

    will a basic buffer be sufficient?

    : Your resistive divider is made up of 5 100Ω resistors totaling only 500Ω. A 1MΩ between GND and the non inverting input should be sufficient. I'm not sure how to answer your "virtual" GND question yet because I have some questions. What is the -12V source to the Buffer + (Buss) through...
  3. CDRIVE

    will a basic buffer be sufficient?

    This one will not work for you because it's an AC coupled amplifier. Chris
  4. CDRIVE

    will a basic buffer be sufficient?

    The OpAmp circuit in your first post is a Voltage follower. It provides unity gain with very a high input Z. It should work well when used with the voltage divider you posted, as it will not load the divider network but will replicate the input voltage on the non inverting input. Chris
  5. CDRIVE

    Need help : Steel conductivity vs LED

    Here's an alternative circuit that checks a 5 conductor cable. It can be easily modified to handle more or less conductors. Chris
  6. CDRIVE

    Dancing Piezo

    I was googling Piezo data and found these on YouTube. The first one is a hoot, hence the title of this topic. The second is a long video but it's worth watching Quartz Crystals being manufactured in 1943. Enjoy, Chris
  7. CDRIVE

    Bike Horn

    While reading through Piezo datasheets I haven't found any that spec anything over a 20V-PP square wave. This link indicates 200VPP but I believe it's a decimal place typo. http://www.discovercircuits.com/DJ-Circuits/beeper4.htm As for my concern about back EMF on the primary .. It's very...
  8. CDRIVE

    Bike Horn

    I'm not sure of a number of things. The Xfmr may not be wired exactly as I've drawn it so I may be revising the schematic. In the past I've made it a habit of giving a big "UGH!" to anything posted from the Instructables website. But like the old saying ... "Sometimes, even a blind Squirrel...
  9. CDRIVE

    Bike Horn

    Ok, so I buy two Chinese bike horns on ebay. One has a brand name of "RockBros" and another that's generic but identical to the RockBros model. Originally, I was going to start this topic in our uC section for those that may be interested in doing what I plan to do. That being,.. replace the uC...
  10. CDRIVE

    Conditioning Electronics

    Ha! There's nothing more refreshing than self deprecation to keep one humble. On another note... I think a blind, deaf and dumb squirrel would conclude that this is a homework assignment. :rolleyes: Chris
  11. CDRIVE

    HUH?????

    It would appear that his aim is to design a frictionless bearing using magnets to levitate a generator rotor. My guess is that he thinks that a frictionless bearing system equates to ... uh, the (ever elusive) perpetual motion machine. What seems to escape his sparsely furnished mind is that the...
  12. CDRIVE

    HUH?????

    The guy has just discovered that magnets can repel each other. Who-duh thunk it??:rolleyes:
  13. CDRIVE

    HUH?????

    Hey, lighten up! That's why it's posted in the Electronics "Chat" section. Technobable can be humorous. Chris
  14. CDRIVE

    HUH?????

    Stumbled upon this youtube vid. Can't wait for the comments from our members. Chris
  15. CDRIVE

    Rest in Peace, Kris

    Donna, thank you so much for enlightening us as to the circumstances of Kris' passing. If you listen to the country song "Three Wooden Crosses" by Randy Travis you may find some solace in the closing lyrics. Those words describe why Kris made such an indelible impression around the entire...
  16. CDRIVE

    Old RS-232 compatibility with new computers?

    I'm going to add another fly to the soup of USB/RS232 converters. I own 5 or 6 of them and have never had an issue with even the most inexpensive (<$10.00) Chinese import. The only one that gives me an issue is an old (relatively expensive) Belkin model and this is only because it doesn't...
  17. CDRIVE

    Simple Switch using Photo Diode

    Hi Alan, I should have asked far more questions regarding Dominos. Heck, I didn't even know that it was played on a board! It's for that reason that the attached circuit may not be applicable but I'm posting it anyway. The Phototransistor can be replaced with a microswitch if desired. As you...
  18. CDRIVE

    Rest in Peace, Kris

    It's been two days since I opened my email and read the notification of Kris' passing. In disbelief I read through all the posts left by many of our members but I didn't post a comment till now. Instead I spent the first day cycling while in a daze, not being able to shake this sad news from my...
  19. CDRIVE

    Simple Switch using Photo Diode

    Sorry for letting this thread drag on so long. I sense that a microswitch sensor is not to your liking but since your ambient light may be very dim that leaves only the option of providing the light source; IE an LED, which will draw more battery power. If you navigate to ebay and search...
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