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  1. Miguel Lopez

    What will happen for Electronics in future

    If you ask such question to somebody, let's say, in the mid 40s (before the transistor was invented), he/she surely would tell you that vacuum tubes will become smaller and smaller. If you ask a clock maker in the end of 19th Century, he would answer that the clocks would be smaller and...
  2. Miguel Lopez

    Variable power supply for supplying valve amp builds

    You can improve that idea, by adding a shunt regulator to the resistor divider circuit.
  3. Miguel Lopez

    transistor help !!

    Hope this help. I guess none of them is suitable for your purposes. S9013 625mW 500mA (it's in the limit) S9014 425mW 100mA S9012 625mW 500mA (it's in the limit) C1815 400mW 150mA I guess you should look for a BD137 type for that application. Then those transistor...
  4. Miguel Lopez

    resistor question?

    Units are only represented with capital letters symbols when they are derived from a person's name. second, meter, mol, candela, radian....etc should always be represented as symbols using non-capital letters. The only exception that I now remember is litre, which can be represented with a...
  5. Miguel Lopez

    Can anyone identify the correct value of this resistor

    Use a knife to rasp the paint near both ends. It should probably be open in one of the end caps. Measure resistance in the resistive material near the ends trying to get continuity. That will give you an idea of the nominal value. Hope this help.
  6. Miguel Lopez

    CP2124P - U0707E

    I will study the PCB. If it looks like a quad OpAmp IC (LM324 type) I will simply replace it with one LM324 to see what happen. Wish me luck. :D
  7. Miguel Lopez

    CP2124P - U0707E

    Here a picture of the IC in the PCB. The only other marking is ICF in front of the IC type. I will try to check what pins are connected to both VCC and GND,
  8. Miguel Lopez

    CP2124P - U0707E

    Package is DIP14. Sorry, I don't remember if it has any manufacturer logo. I have it at home, I will check today
  9. Miguel Lopez

    CP2124P - U0707E

    Hello everyone I'm looking for the datasheet of an IC with the markings CP2124P and U0707E. Don't know which of them is the IC type. I have not found them in "alldatasheet.com" using both markings. It might be something similar to LM324 or LM339, cause it is the IC present in a fridge...
  10. Miguel Lopez

    Need help with Wien-Bridge Oscillator

    By changing only one potentiometer (R) it is also possible to change frequency, but not linearly. The tandem pot is no strictly required, but that's a more elegant way to do it.
  11. Miguel Lopez

    Two Leg Transistor

    Something like this? Third terminal is the case, but it has only two legs I know transistors with only one junction, but I guess there are not transistors with ONLY two terminals
  12. Miguel Lopez

    Variable power supply for supplying valve amp builds

    Sorry Chris. I apologize for the misunderstanding. Please, be more especific next time. I would have to calculate (or simulate) those values. Sorry. It will take some time. Try these examples:
  13. Miguel Lopez

    Variable power supply for supplying valve amp builds

    Here is the schematic with the values that I used. To increase the output voltage, you must increase the value of Vnr, the 100k potentiometrer should be increased too (depending on the output needed), the transistors must be selected properly, etc. Several calculations have to be made. I...
  14. Miguel Lopez

    Variable power supply for supplying valve amp builds

    I know Chris. It was just an example. By adjusting components values, he can get the desired voltage. Come on Steve.:) I was talking about the first image in my post. Althought, thinking better on it....with proper wiring and ECL82 could be considered like that. :eek: If there were valve...
  15. Miguel Lopez

    Variable power supply for supplying valve amp builds

    A valve regulator would do the job. What duke37 says is very important cause the heater-cathode insulation has limits. See the attachment #1. I once designed a circuit for this purpose for a friend, using transistors. The schematic includes a current protection circuit and a rapid discharge...
  16. Miguel Lopez

    Problem - Triangle Wave Generator

    Mount it in a protoboard or similar. It should work. That circuit is almost infallible.
  17. Miguel Lopez

    Problem - Triangle Wave Generator

    Doesn't you circuit work in Proteus or in the real world? I had some similar problem using EWB 5.1. But in the protoboard it worked fine
  18. Miguel Lopez

    Cuban Cuchufleta

    That's right. The cuchufleta has evolved from pushbike dynamos to car alternators, but the principle to move the axis is the same (+/-)
  19. Miguel Lopez

    Cuban Cuchufleta

    In another thread, we were talking about the possibility to obtain energy from a water hose. As that thread was closed, and I didn't know where exactly to open this one, I open it here. If this is the wrong place, I beg the Mods to move it to the right place. The term "cuchufleta" is the name...
  20. Miguel Lopez

    Making Digital Clock Programmable

    And you will need some way to neutralize the bouncing effect on the button. A bistable can do the job. The button should be in logical OR with the pulses which clock the hours and minutes.
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