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  1. audioguru2

    Current problems of TIP122

    Why are you using the TIP122 darlington to short the 3V battery? The collector and emitter currents will be whatever the shorted battery current will be which might be 8A if the cells are new or be a few mA if they are old. The current gain of a TIP122 is a range from 1000 (the minimum) for some...
  2. audioguru2

    Parts suppliers

    How do you know which ebay Chinese part is a fake and which one is real and good that will work?
  3. audioguru2

    Parts suppliers

    A local trustworthy electronics parts distributor sells good reliable parts. Some are made in China. The reliable parts are not bought on ebay by the trustworthy distributor. There are entire Chinese cities that make only fake electronic parts or they are factory rejects that are sold on ebay.  
  4. audioguru2

    Parts suppliers

    Newark is also a good electronic parts supplier.
  5. audioguru2

    A modern day 0 - 30V, 0 - 3A Linear Power Supply?

    The ebay kit that is a copy of the original faulty Greek power supply on this site is also sold by Banggood and Amazon. Banggood is selling it at a clearance price since they probably had many complaints. They have modified it a little and are selling it again as a kit with a 28V/2A rating and...
  6. audioguru2

    Power supply

    You forgot to say if the 10V output from your power supply must be AC or DC. You also forgot to say if the input is AC or DC and its voltage and frequency. Did you know that the output power from your power supply will be 10V x 1000A= 10000 Watts? Where will it come from? What will it be used for?
  7. audioguru2

    How to adapt Li-ion batteries to replace AA batteries

    mAh is how long a battery will supply the current, not its maximum current. Besides, a load only draws as much current that it uses and not more unless it is shorted. Your car battery can provide hundreds of Amps to the starter when it is cold but the clock uses only a few thousandths of an Amp...
  8. audioguru2

    DC-DC Converter

    Your attachments do not work. Usually a circuit built on a solderless breadboard with messy wiring all over the place and intermittent contacts does not work. I have designed and built thousands of prototype circuits, some VERY complicated, soldered together on a compact stripboard layout and...
  9. audioguru2

    basic electronics lab experiment single stage CE amplifier

    The very simple kit should have told you what Vcc is and what Vi and Vo are.
  10. audioguru2

    simple question about switch,wattage,loading...

    You said it is rated at only 24W. Why are you overloading it with 10 times too much load?
  11. audioguru2

    how to make a mailbox light? guys

    The cheap Chinese solar garden light has a dim light for only a couple of hours following a sunny day. It lasts only a couple of months before its LED, solar panel and battery rust away. No light following a cloudy day. The cheap solar panel actually gets sunburned. Use the pcb circuit from a...
  12. audioguru2

    Bad quality breadboard?

    Solderless breadboards cause many problems reported on all the electronic forums. The many tangled wires and rows of contacts have capacitance between them that cause many electronic circuits not to work properly. The contacts are frequently intermittent. I made thousands of prototype circuits...
  13. audioguru2

    0-30V 0-3A Latest Data

    To use your transformer then many resistor values will need to be re-calculated and changed. The 16.6VAC will have a peak voltage of only 23.5V. The improved circuit is designed to use a 28VAC/4.3A or 30VAC/4A transformer. If you re-design the circuit then with your transformer its maximum...
  14. audioguru2

    FM Transmitter

    I talked in ordinary electronics terms. Since you do not understand electronics then I cannot explain it better. Why do you need a radio transmitter that might cause illegal interference with radio stations and important communications?
  15. audioguru2

    0-30V 0-3A Latest Data

    Look at the schematic above on October 30, 2016 where it shows the RV3 trimpot that sets the current limit calibration accurately.
  16. audioguru2

    FM Transmitter

    Here in Canada (and in the USA) FM radio station frequencies are at odd frequencies like 99.9MHz, 100.1MHz, 100.3MHz so 100.0MHz is not used. Even frequencies like 100.0MHz, 100.2MHz and 100.4MHz might be used in Europe. If you use a quartz crystal oscillator and a harmonic of it at 100.0MHz...
  17. audioguru2

    Transformer for voltage booster?

    It is inefficient to boost the voltage too high then drop it down. Why does the amplifier need a supply of 140V to produce only 100V? Won't the extra 40V cause lots of power waste as heat?
  18. audioguru2

    0-30 Vdc Stabilized Power Supply

    February 23 above on this page has the latest schematic of the revised 3A lab power supply.
  19. audioguru2

    0-30 Vdc Stabilized Power Supply

    I do not know which circuit the ebay pcb uses, maybe it is wrong. The original circuit and the ones modified on this website use a 0.47 ohm current sensing resistor R7. Then when the current setting pot is turned to maximum the current is limited to about 3.0A. The Chinese modification for the...
  20. audioguru2

    How to find electronic parts?

    I buy electronic parts from Digikey and Newark because they have offices and warehouses in my country and they stock everything. What can't you find?
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