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  1. C

    Identification help

    For 4 digit resistors you write the first three digits and the 4th digit is the number of zero's. So that 2210 is 221 and no added zeros = 221 ohms
  2. C

    Resistance of Primary Winding of a Transformer

    That's a very good price. The website says $33 delivery and no other delivery prices are provided.
  3. C

    Resistance of Primary Winding of a Transformer

    It looks like it was only single sided. What was the delivery charge?
  4. C

    Resistance of Primary Winding of a Transformer

    What did it cost you?
  5. C

    Resistance of Primary Winding of a Transformer

    I am very clever. I am multi-talented. I can answer your question and provide an answer to the best PCB maker in China, AT THE SAME TIME ! I have tried lots of PCB makers and they are all a rip-off. I pay $15.00 for 100mm x 100mm 10 boards. double sided. One supplier wanted $420 USD !! I get 2...
  6. C

    Resistance of Primary Winding of a Transformer

    I haven't given you a link.
  7. C

    Resistance of Primary Winding of a Transformer

    I have so many transformer explanations on my website, it took me 30 minutes to find the relevant section. I have posted it above.
  8. C

    Resistance of Primary Winding of a Transformer

    Here is something I have on my website as an answer to an argument with a moderator on a forum: HOW THE TRANSFORMER WORKS The first item you need to study is the TRANSFORMER. It's the main component of the power supply and appears to be the simplest. But there is a lot to know about how it...
  9. C

    Resistance of Primary Winding of a Transformer

    I have explained how a transformer works on my site Talking Electronics.com. The main reason why the transformer does not "blow a fuse" is because it produces a "back voltage" of nearly 95% - 99% of the supply voltage and thus the actual voltage entering the transformer is just 1v to 5v and at...
  10. C

    Non Micro-Controller LED Array Control?

    "If you want a digital display of voltage, the old way involved a dedicated voltmeter IC such as the Intersil ICL7106:" You can buy a digital voltmeter on eBay for $3.00
  11. C

    seeking explanation on basic led flashing circuit

    "It's not really a matter of "energy in" CT being "passed to" Q1B." That's one of the most important points. The capacitor is already charged to 650mV and this energy is removed from the capacitor during the time when the two transistors start to turn ON. "This current causes the voltage...
  12. C

    Non Micro-Controller LED Array Control?

    By the time you use 3 discrete chips, you could have used a 30 cent micro.
  13. C

    seeking explanation on basic led flashing circuit

    There are a couple of points that have not been emphasised. The first point is the fact that the second transistor must be in a high-current situation so that it requires a high base current at some point in the cycle. The second feature to visualise is the fact that the capacitor is doing all...
  14. C

    7 led chaser 555 and 4017

    What are you illuminating?
  15. C

    SMD Capacitor identification

    They will not be "bad."
  16. C

    Modify circuit to add switch and timer

    What is the point of C1, C4, R1 and Q1 ??? You will find this circuit is unsuitable as it only works when the foot is placed on the ground. It needs to work when the foot is lifted.
  17. C

    Modify circuit to add switch and timer

    The $1.00 alarm is not suitable for your application. It produces a beeping alarm
  18. C

    Modify circuit to add switch and timer

    Colin, this post helps no one at all. Please don't waste space and time posting useless comments like this. I want the OP to get back and place a comment. So many times I answer these forums and the OP never bothers to get back.
  19. C

    Modify circuit to add switch and timer

    You just need a couple of electrolytics and a few resistors.
  20. C

    Transformer/Coil

    The numbers on the diodes and capacitors will help work out if the output is 100v or 1,000v
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