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  1. Herschel Peeler

    Apple vs the FBI

    Good questions. If you rent an apartment to a person and in doing a background check you find out they are wanted for murder are you obligated to call the cops? So many good questions on this topic. ood
  2. Herschel Peeler

    JFETs as a current source and a question.

    Re: simulated circuit hanks for that. I gotta learn to use an simulator.
  3. Herschel Peeler

    Apple vs the FBI

    The FBI should have the talent???? Now there is an idea. :-) That little lady on NCIS does it all the time. :-) So many devices. So many programs. So many versions of each. Does the industry need to be well regulated like the casino gaming industry? Before a product can be released the software...
  4. Herschel Peeler

    Apple vs the FBI

    All some very good arguments for a very complex topic!! It is just not as simple as any one side would have it. Personally, I would support the needs of law enforcement to investigate. But them I am told I would be comfortable in Russia. :-)
  5. Herschel Peeler

    Apple vs the FBI

    If the meta data shows them calling known terrorists shouldn't that justify a warrant? You don't need to encrypt a message to your mother.
  6. Herschel Peeler

    Apple vs the FBI

    A nice thought but we can't wait until after the bombing and convict the remains of the bomber. To protect the public we need to investigate and act before the crime.
  7. Herschel Peeler

    JFETs as a current source and a question.

    But the transistor on the far left has no gain. The others should, or at least it would seem. The current design has 5.5 mA going in, but about 8 mA at the outputs. The transistors are not in saturation. About 2.7 V out. ??? Because of the constant voltage drop across the LED ??? Still using the...
  8. Herschel Peeler

    Apple vs the FBI

    I can see the point of that.
  9. Herschel Peeler

    Apple vs the FBI

    Do terrorists deserve privacy? I can see a need for a warrant, for sure. But I would like the FBI to have the tools to fight crime. Do we have privacy if hackers develop the software? There is, in deed, a danger of it slipping out of the proper controls, but we have that danger of hackers...
  10. Herschel Peeler

    JFETs as a current source and a question.

    Something like this? No need for the odd ball transistor array.
  11. Herschel Peeler

    JFETs as a current source and a question.

    I'll try that. In op amps the current mirrors have emitter resistors on them. Used to trim offset!!! So I should be able to trim my outputs by trimming the emitter resistors. Sounds good. Thanks.
  12. Herschel Peeler

    JFETs as a current source and a question.

    Maybe part of my problem is not understanding current mirrors? Why does the output transistor have no gain? In a simple current mirror, one input,, one output, why is collector current the same as base current? Or is that the case? Is the input current split between the two bases? So the base...
  13. Herschel Peeler

    Apple vs the FBI

    Unless Apple wants to deliberately be on the side of crime all they have to say is that using the encryption for criminal activity may wave rights to secrecy. Create the software! Will it only be a matter of time before some unhappy Apple programmer takes the opportunity to do it himself? How...
  14. Herschel Peeler

    JFETs as a current source and a question.

    That makes sense, of course. As I add more transistors to the constant current source ... my current just divides between the transistor's bases??? Then my output currents should divide accordingly ??? They don't. They stay to about 4 mA or so. On a gain check all my transistors match well on...
  15. Herschel Peeler

    JFETs as a current source and a question.

    Okay, replaced the JFET circuit with just a resistor (820 Ohms). Voltage and current through the resistor did not change very much with no LEDs, or 4 LEDs. Adding loads on the collector does not change base current proportionally, no surprise I guess. But this sheds no light on why my four...
  16. Herschel Peeler

    JFETs as a current source and a question.

    Super, thank you. Now add more transistors in parallel with Q2. Does the source current stay the same? On my breadboard it does. It does not increase as I add loads on the "Q2"s collectors. Is that 5 mA split between the bases of all transistors, no matter how many there are? I will try...
  17. Herschel Peeler

    JFETs as a current source and a question.

    Re: Vcb = 0 V. The driving side is as you say. Re: Trying it with just one LED. No change. And the driving side current stays at 5.5 mA no matter how many LEDs are connected, or none. ???? The transistor array was the closest thing I had to matched transistors. I thought they would be matched...
  18. Herschel Peeler

    JFETs as a current source and a question.

    Getting to play with Junction FETs, discovering them as a current source. I had three on hand; 2N3819 N-JFET, PN5433 N-JFET and 2N5462 P-JET. I did the attached exercises in the configurations shown in the schematic. Each exercise means building it with all resistors, 10 ohm to 1 M ohm and...
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