Search results

Search Forums New Posts
  1. bertus

    Buying a Digital Oscilloscope.

    Hello, For what applications do you want to use the scope? What features do you need? https://www.cwtouchkeyer.com/best-digital-oscilloscopes/ https://www.mouser.com/pdfdocs/Tektronix12_things_to_consider1.pdf Bertus
  2. bertus

    Car radio gets only static need help troubleshooting

    Hello, Do I see L001 next to the part? Than it could be an inductor: http://www.ibselectronics.com/ibsstore/chilsin-nl4532325t-4r7k-inductor-4-7uh-10-smt-smd.html If it is indeed an inductor, it should measure very low resistance. Bertus
  3. bertus

    Replacing NIMH batteries

    Hello, With the 750 mAh you will have about half the runtime of the 1500 mAh batteries. I can be that the 750 mAh batteries will be heaten up by the charger, as the charging current will likely be to high. Bertus
  4. bertus

    Car radio gets only static need help troubleshooting

    Hello, The 4R7K is a manufacturers marking. Have a look at newark: https://www.newark.com/tt-electronics-welwyn/emc2-4r7k/through-hole-metal-film-resistor/dp/34R3442 The K stands for 10 % tollerance. Bertus
  5. bertus

    Need help identifying part number for transistors.

    Hello, The part with 1254 could be a fake 2N1254. The origenal 2N1254 is in a metal TO-5 housing. From the Transistor Taschen Tabelle: Bertus
  6. bertus

    TRIAC

    Hello, The optocoupler is off at the moment of startup. R6 and C4 are the time elements. When C4 gets charged enough, the optocoupler is activated. Bertus
  7. bertus

    TRIAC

    Hello, The output of the optocoupler is shorting R10 when activated. Shorting R10 changed the timing of the triac, giving more power on its output. Bertus
  8. bertus

    TRIAC

    Hello, The transistor of the optocoupler is free from any potential, so it is basicaly used as a floating switch controlled by the led of the optocoupler. Bertus
  9. bertus

    BC547 transistor

    Hello, @Alec_t , I have added the line. Bertus
  10. bertus

    TRIAC

    Hello, The optocoupler is probably used as a floating switch. Bertus
  11. bertus

    BC547 transistor

    Hello, Have a look at the following page for more info on the transistor astable multivibrator: https://www.electronics-tutorials.ws/waveforms/astable.html Bertus
  12. bertus

    Need help identifying part number for transistors.

    Hello Wich transistors do you have? There are also data books in the resources: databooks on the internet archive and bitsavers Bertus
  13. bertus

    TRIAC

    Hello, @Minder , It looks like a circuit for some kind of soft start. The circuit before the using C4 as time delay. When the delay is over, resistor R10 is shorted to have higher power. Bertus
  14. bertus

    Need help identifying part number for transistors.

    Hello, I could find the big one: https://www.alldatasheet.com/datasheet-pdf/pdf/1073860/NJSEMI/MPS-U52.html Bertus
  15. bertus

    using bjt amplifier to obtain a current higher than the maximum current an arduino can output

    Hello, I mean as series resistor between the arduino output and the base of the transistor. Bertus
  16. bertus

    using bjt amplifier to obtain a current higher than the maximum current an arduino can output

    Hello, Move the resistor from the emittor to the base. Bertus
  17. bertus

    Part id

    Hello, There is no image, but I copied and cropped the image from AllAboutCircuits: Unfortunately it is out of focus. Are there also some markings on the other side of the part? Bertus
  18. bertus

    Lm358 as an RF "amplifier" : possible ?

    Hello, If you want some more serious reading about RF detectors, have a look at the following pages: https://www.maximintegrated.com/en/design/technical-documents/app-notes/5/5085.html https://www.reddit.com/r/rfelectronics/comments/8lh3hm/rf_detector_circuit_for_listening_devices_and/ Bertus
  19. bertus

    Bringing an old Stargate console to life - after cleaning

    Hello, Keep in mind that the CRT has high voltage. Dust and moisture can cause arcing in the HV area of the CRT tube. Also the HV can stay quite some time on the CRT tube. Have a look at the safety guidelines: http://www.repairfaq.org/sam/safety.htm Here are also some guidelines for reparing tv...
  20. bertus

    Lm358 as an RF "amplifier" : possible ?

    Hello, No, the LM358 has only a bandwidth of 1 MHz, on 1 MHz the gain is only 1. There is not even a selective circuit and RF detector shown. It will respond to ALL RF signals very close by. bertus
View older results
Top