Search results

Search Forums New Posts
  1. D

    temperature control switch

    You can also code in block language with : https://picaxe.com/ https://picaxe.com/software/ blockly download Regards, Dana.
  2. D

    [HELP]Led dimmer

    Some questions : 1) Do you know how to code in C or using block languages like scratch or mBlock ? 2) Familiar with using Arduino ? 3) Your garage LED lights a dimmable string or just a 110 VAC plugin string ? Regards, Dana.
  3. D

    Scavenging replacement MOSFET

    The TIP41C is a bipolar NPN transistor. You have a schematic we can look at ? To seek clues as to what is needed. Regards, Dana.
  4. D

    Replacement

    Thats correct, JRC is fine. Regards, Dana.
  5. D

    Replacement

    Schematic for the circuit, and what does the circuit do ? You can still buy 4558 : https://www.digikey.com/en/products/filter/instrumentation-op-amps-buffer-amps/687?s=N4IgTCBcDaICwFYEA4QF0C%2BQ Regards, Dana.
  6. D

    Get oscillator

    Voltage Regulator oscillator : Regards, Dana.
  7. D

    Lcd display issue

    This might help : https://www.youtube.com/results?search_query=lcd+zebra+strip Regards, Dana.
  8. D

    CONVERT from 15-0-15v to 9v

    Single supply sine generators : https://www.ti.com/lit/an/slyt164/slyt164.pdf?ts=1665140158285&ref_url=https%253A%252F%252Fduckduckgo.com%252F Single supply considerations : https://www.ti.com/lit/an/sloa030a/sloa030a.pdf...
  9. D

    BJT Cascode Amplifier

    A partial solution flow - https://www.bg-elektronik.dk/generally/transistor/Cascode%20Amplifier%20Design.pdf Regards, Dana.
  10. D

    Max7219 is making a lot of noise

    Not all caps perform equally as bypass for the same capacitance, eg. ESR specs. Polymer tants best for bulk, and your LEDs causing lots of current noise. paralleled with ceramics for high freq suppression as well. OS-CON is polymer tant..... Regards, Dana.
  11. D

    Power jitters

    What is your scopes model number ? If you have FFT in scope you can look at harmonics to get clues to sources. Probing mains : https://download.tek.com/document/3AW_19134_2_MR_Letter.pdf Regards, Dana.
  12. D

    Combining Micro Generators

    Some ref material : https://www.ti.com/lit/an/slvae57b/slvae57b.pdf?ts=1664544415236&ref_url=https%253A%252F%252Fduckduckgo.com%252F If trying to do max efficiency ...
  13. D

    Capacitance rules...

    https://www.khanacademy.org/test-prep/mcat/physical-processes/capacitors/v/capacitors-series Regards, Dana.
  14. D

    P-MOS control and capactive load

    Use a higher Vceo PNP than 100V.....give yourself some margin. The BD140 was only a web example of the source, just pick a 200V part with ratings you need. Regards, Dana.
  15. D

    How to connect a 5v micro vacuum pump to a Raspberry Pi 4 computer model B

    What is the pump datasheet and electrical specs ? You want to speed control it or just turn on/off with Pi ? Regards, Dana.
  16. D

    P-MOS control and capactive load

    Actually you cannot use the LM317,. my error, does not have enough HV capability. Use a PNP version of one of these or or Two diodes below could be a LV zener. Regards, Dana.
  17. D

    P-MOS control and capactive load

    I am not concerned about the power then. But low ESR cap thats means the fet is looking into almost a dead short with 100V across it, which must be violating SOA if I read the SOA chart right. What is its ESR ? And for sure the Litiums are low esr as well. You could run a quick turn on test...
  18. D

    P-MOS control and capactive load

    Thats peak power not avg power which would be a lot lower because of the duty cycle is so low. What freq do you drive the circuit ? Your gate drive R's, 100K, 20k, can make the mosfet switch faster and lower the avg power if they are significantly reduced. But that means the peak drain current...
  19. D

    P-MOS control and capactive load

    You are operating the IRFR9120 right at its spec Vds breakdown so there is no margin there for starters. Plus you have it in the active region a long time due to slow gate charging so its dissipating a lot of power potentially. And I am guessing you may be violating SOA : How rapidly do you...
  20. D

    Working around garbled LCD display on a blood-pressure monitor

    I could not tell in pic of display with ribbon exiting left if on backside there is a zebra strip between ribbon and display ..... But no expert here am I. Regards, Dana.
Top