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  1. Cirkit

    Ceramic capacitors substitute

    Thanks for your reply (*steve*), I've been refreshing my knowledge and some types of film capacitors are indeed preferred in applications that need frequency stability e.g.Polypropylene. So would this Vishay PolyTant be suitable for use in an oscillator circuit: T55P475M010C0200 (0.2 Ohms...
  2. Cirkit

    Ceramic capacitors substitute

    I was reading some of the manufacturer's white papers and they claim that polymer technology is superior to MLCCs. For example the Panasonic POSCAP or OS-CON...
  3. Cirkit

    Ceramic capacitors substitute

    I have been reading about the global shortage of MLCCs and also how the properties of ceramic capacitors can vary if the PCB is flexed. Some manufacturers are recommended the use of newer polymer (electrolytic) capacitors as an alternative. Can polymer capacitors be substituted where a ceramic...
  4. Cirkit

    Non-inverting audio Op-Amp

    No it's an intermediate stage before feeding a differential output stage for an XLR connection.
  5. Cirkit

    Non-inverting audio Op-Amp

    R1 is currently 10k and R2 4.7k. That equates to a voltage gain of about 3. I need to reduce the output from the Op-Amp not the signal entering it. Based on some audio measurements, I need a 15 to 20dB reduction. How does that translate to voltage gain? Do I subtract 0.1 (-20dB converted...
  6. Cirkit

    Non-inverting audio Op-Amp

    I am trying the reduce the gain of a non-inverting Op-Amp circuit used as an audio pre-Amp. I have measured the output and need to reduce the audio level by about 20dB. How do I calculate the correct resistor value change? Is it a linear relationship or do I need to convert dB gain to voltage...
  7. Cirkit

    433MHz door bell - Tx antenna feed

    I am trying to work out whether the component indicated by an arrow in the photo in the antenna feed, is a capacitor and what its value is likely to be? I have tried measuring it with a few different meters and it reads open circuit in resistance and capacitance mode which makes me think it...
  8. Cirkit

    Constant current LED drivers - faulty, flashing panels

    I have tried it on both a halogen and LED lamp rated at 240V but both flash on and off. I supose both of these present a high load. The drivers come supplied with the panels. They are designed to work with them.
  9. Cirkit

    Exposed Adapter, Uncertain.

    If it's on the low voltage side of your adapter that plugs into your keyboard, then you can use some heatshrink or electrical tape will also be fine if you are concerned about it being exposed.
  10. Cirkit

    20-30V input 12v high current output regulator, not working

    Do you have to specifically use a linear regulator in your design? Using a switching buck-converter would be more efficient. There are relatively cheap modules you can just buy and use: https://www.amazon.co.uk/Gaoxing-Tech-LM2596HVS-Adjustable-Converter/dp/B06W9K7GK7
  11. Cirkit

    Constant current LED drivers - faulty, flashing panels

    The drivers are correct as the manufacturer has supplied some identical model replacements and they have been working fine for over a year with the same LED panels. I just want to determine the cause of the fault and repair the faulty drivers to have as spare. Most LED panel drivers (across...
  12. Cirkit

    Constant current LED drivers - faulty, flashing panels

    When you say 33Ω or less, how much less? Would a halogen lamp be too low resistance? I'm not sure as it's too large to measure using the diode range on a meter. I'm guessing somewhere between 33-40V typically?
  13. Cirkit

    3.3v circuit from a LiPo cel

    If you have a spare output port on the microcontroller, you could use it to switch a 3.3V LDO when the Wi-Fi module is required. Have you worked out the current profile of your circuit and how long it needs to last on one charge?
  14. Cirkit

    Constant current LED drivers - faulty, flashing panels

    I have come across a few faulty LED drivers which cause the LED panels to flash on and off. Often this occurs after the driver/panel has been left switched on for a while. I've opened the drivers up and noticed some swelled capacitors - usually on the primary side i.e. the main 400V capacitor...
  15. Cirkit

    DC-DC converter

    Searching other sites for similar specifications, looks like a VB1212S-1W which is a 12V 1W isolated DC-DC with 68% efficiency.
  16. Cirkit

    DC-DC converter

    One of the reviews for that regulator mentions that the output voltage is slightly higher. I believe that regulator has a 1W output? Try connecting a 200 Ohm 1W resistor directly across the output of the regulator with nothing else connected and measuring the voltage. Is it closer to 12V...
  17. Cirkit

    Blown multimeter fuse again - Doh!

    Any of the Gossen Metrawatt ones. I think Hioki also do one.
  18. Cirkit

    Blown multimeter fuse again - Doh!

    I have done that but luckily, so far I don't think it's resulted in a blown fuse yet! One of my meters has shutters on the terminals so you cannot select the voltage range or vice-versa without removing the lead plugs from the incorrect terminals.
  19. Cirkit

    Blown multimeter fuse again - Doh!

    Thanks, but I wasn't blaming the meter - just frustration that's all! :mad: So do you never blow fuses at all?
  20. Cirkit

    Blown multimeter fuse again - Doh!

    Is it just me or do others infrequently blow multimeter fuses when measuring current? :( I use the lower range current terminals when I think the current consumption is going to be lower than the fuse rating but the circuit being tested often doesn't behave as expected and tries to draw the...
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