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  1. Herschel Peeler

    Modified meter lead for breadboards.

    Attached. Picture of the breadboards, leads and LED exercise with a red LED. The small breadboard off to the side is the boosted LM78L05 voltage regulator and two variable voltage sources. Towards the bottom two voltmeters are shown. Inside the box are two 15 Volt sources of AA batteries and...
  2. Herschel Peeler

    Voltage on a white LED.

    The bag said RL5-W18030. I buy them by the 100. I didn't note the manufacturer. "Superbrightleds.com" it says Sorry for the error in the original post. "10,000 Lm" has been corrected to 18,000 mcd".
  3. Herschel Peeler

    Modified meter lead for breadboards.

    I often have need for more than one meter on breadboard projects. I modify the leads with pins that fit smoothly into the breadboard. Jameco part number 185421. Cost about $0.07 each purchased in quantity of 10. Crimp, solder and heat shrink. Favorite meter currently is from Electronic Goldmine...
  4. Herschel Peeler

    Wattage on things

    A 2000 Watt power supply does not put out 2000 Watts necessarily. It can put out UP TO 2000 Watts. Less is okay. Providing, as stated, voltage and all is correct.
  5. Herschel Peeler

    Maplin Electronics in the USA?

    Well, it is good to see big brother is watching. Bob and I seem to have a different experience. You must have been buying n quite a quantity to get noticed. I've been doing electronics for 50 years also and nobody has come to visit me. And yes, I agree selling transistors and Is does not cover...
  6. Herschel Peeler

    Voltage on a white LED.

    Thank you, yes, 10,000 mcd.
  7. Herschel Peeler

    Voltage on a white LED.

    Re: heat sinks On T5 size LEDs for instance you can solder a bit (0.5 sq in) of copper foil to the cathode lead.
  8. Herschel Peeler

    Voltage on a white LED.

    Just because the data sheet says 3.5 V at 20 mA it does not mean it must be used that way. Here is an exercise riving a white LED at different currents. Above is the schematic used. I started at the low end and increased current until the LED lit up. To my surprise the LED was almost always lit...
  9. Herschel Peeler

    8051 power supply

    I don't have anything for the 8951 but all other microcontroller programmers I have bought come with programming software or have it available for downloading on the Internet, along with examples. Lots of available help for hardware or software. My preference is programmers with sockets so I can...
  10. Herschel Peeler

    8051 power supply

    "better" depends on your application.
  11. Herschel Peeler

    8051 power supply

    Looks quite suitable.
  12. Herschel Peeler

    Output Amplifier for a project

    Yep, pretty standard push-pull. The nice feature is T9 and T18 as current limiting circuits to protect T8 and T19. For example T8 and T9. As T8 emitter current increases the voltage drop across the emitter resistors reaches about 0.6 V and T9 starts to conduct dragging down the signal going to...
  13. Herschel Peeler

    Milliamp power supply question

    I agree with Audioguru. Stay as close as possible to the current you need. Or you can build a regulator to bring the voltage down to fit your needs. I have quite a collection of such supplies myself and as long as I have one with Watts close to fit my needs I can bring voltage up or down as...
  14. Herschel Peeler

    Voltage Drop across NPN BJT C&E?

    Got it. Thank you for your words on this and patience.
  15. Herschel Peeler

    Voltage Drop across NPN BJT C&E?

    Ah, yes. At as low a base current as I was working Vbe changes so little I couldn't measure it.
  16. Herschel Peeler

    Stair Ways light controller

  17. Herschel Peeler

    8051 power supply

    My inventory list says I have a bunch of 8751s in storage along with a bunch of related stuff I don't intend to use in the future. Would you like a small box of stuff? I will be glad to see them get a good home. My email is [email protected]
  18. Herschel Peeler

    8051 power supply

    The 8051 is the programmed (ROM) version it seems as I remember. 8031 is the ROMless version, 8751 is EPROM version. All can be set to use external EPROM, but it ties up all but one port. You can build a stand-alone manual programmer. I remember seeing a schematic for it but never built it...
  19. Herschel Peeler

    Voltage Drop across NPN BJT C&E?

    Yes, changing Vbe does change Ic ,,, which changes Vce. Is Vbe an indicator of Ic? In the example attached I can change Ic which changes Vce, but Vbe does not change. We cannot derive Ic or Vce from Vbe. Certainly Ib or Vb changes Ic and Vce, but I don't see how we can calculate Ie or Vce by...
  20. Herschel Peeler

    Voltage Drop across NPN BJT C&E?

    What you say makes sense and I can see it working in a current mirror of a differential amplifier, but I must be missing something. I I hold Vbe and Ib constant and change Ic Vce changes (and beta). So how can we say Vbe controls Vce? What is controlling what? Ice controls Vce and beta. Vbe...
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