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  1. Audioguru

    novelty led blinker, how is it done?

    All my life I dreamed about floating above everything (flying) not from looming death but instead from feeling freedom to do what I want whenever I want. My heart attack and septic shock were very sudden and I am lucky they occurred at home and my wife drove me to the hospital 5 minutes away...
  2. Audioguru

    novelty led blinker, how is it done?

    Hevans, I am sorry to her about your medical problems. I also thought my end was near during my heart attack 10 years ago and a septic shock blood poisoning last year but the doctors fixed me quickly and I bounced back. The doctors also gave me improved vision (cataracts surgery with synthetic...
  3. Audioguru

    novelty led blinker, how is it done?

    The warranty for my hearing aids ran out about 1 year ago so I recently bought a pack of zinc-air cells from Costco. They last 10 days (turned off each night) so the cost is less than $9.00Can for each one per year. They do not have LEDs. Hevans, I am sorry to hear that your brother passed...
  4. Audioguru

    novelty led blinker, how is it done?

    Years ago, I made some LED chasers. I used high current Cmos 4017 ICs called 74HC4017 and a Cmos inverters IC making the oscillator and the mono-stable momentary blink from each LED. Two AA battery cells last for 3 months blinking day and night. 10 LEDs blink around the circle in about 4 seconds...
  5. Audioguru

    novelty led blinker, how is it done?

    Button batteries have a very small amount of chemicals so they light LEDs for only a few minutes, dimming all the short time.
  6. Audioguru

    Increasing Battery life Question

    The contacts on a battery holder for size D alkaline cells probably overheats with only 2A. of course a "super heavy duty" Chinese carbon-zinc size D cell probably has a low capacity of only 1Ah.
  7. Audioguru

    27Mhz FM Transmitter and receiver circuit.

    The MC2833 IC is obsolete and is not made anymore. I think CB radio is also obsolete.
  8. Audioguru

    Something most people have heard but never seen

    100V was used in stores and shopping malls but 25V was used is schools so that the little kids running around in the ceiling did not get electrocuted.
  9. Audioguru

    27Mhz FM Transmitter and receiver circuit.

    Toys used 27MHz for radio control and CB radio many years ago. FM was not used, instead AM or pulses were used. FM modulates the frequency so it would be difficult to modulate the frequency of a crystal oscillator.
  10. Audioguru

    Transistor alternative

    You probably will not find the datasheet of an antique BEL187 which was from India. The transistor symbols on the schematic show NPN, I do not know why you were told to use a BC327 which is PNP. Since an ordinary 5mm LED uses only 20mA then BC547 transistors will work fine for all three in that...
  11. Audioguru

    Tesla coil driver mosfet problems.

    The schematic shows two series diodes forward biased by 60VDC! It also shows a P-channel Mosfet in a circuit that needs an N-channel Mosfet. Hey, maybe the 60VDC power supply is backwards instead? Then there are more schematics and more errors. The questions from "We" indicate schoolwork.
  12. Audioguru

    Li-Ion battery: Too much voltage?

    How will you measure 50% capacity? Do you have a circuit that averages the current drawn over time? The voltage will be high with no load then it drops way down when loaded so the voltage cannot be used to determine remaining or used capacity.
  13. Audioguru

    Li-Ion battery: Too much voltage?

    I do not know what speed you normally run the motor at and do not know how many Ampere Hours you need for a battery. Maybe 50Ah if you average 10A for 5 hours? The little 18650 cells are only 2.5Ah so you would need 50/2.5= 20 banks of four cells in series which is 200 cells. Reducing their...
  14. Audioguru

    Li-Ion battery: Too much voltage?

    An ordinary "3.7V" Lithium cell is 4.2V when fully charged. Then four in series make 16.8V which is too high for your system. Previously you were told to throw away the extra voltage with some very hot diodes.
  15. Audioguru

    Will 13v led lamps run on 12v?

    Dmc112 keeps talking about using a high current transformer to blow up the LEDs. He doesn't understand that a transformer has an AC output. The LED lights are designed to be used with the constant current 700mA DC power supplies for each light as shown. I agree that those 700mA AC/DC power...
  16. Audioguru

    AC TO DC with Op amp

    Since you know nothing about high voltage electricity that can kill you, then you should buy a power supply that gives the plus and minus 5VDC at whatever current you need. You were shown the power supply schematic on your other thread. Why did you make this thread??
  17. Audioguru

    2-channel passive mixer-independent volume control for each pickup

    Looking again, it looks like guitar preamp outputs have a high output resistance so that their volume control can be connected backwards. When one preamp volume control is turned down to short its output level then the other preamp output level is not reduced. I call it Mickey Mouse mixing.
  18. Audioguru

    2-channel passive mixer-independent volume control for each pickup

    The volume controls for the pickup preamps are connected backwards. They short circuit the preamp output and also the other preamp output to reduce their levels instead of using each volume control as a separate voltage divider. The master volume control is wired correctly as a voltage divider...
  19. Audioguru

    2-channel passive mixer-independent volume control for each pickup

    If the output impedance of each preamp is crazy at 3.5k and you add un-needed 4.7k resistors in series with them and connect them to a 10k blend pot then you will have a reduced output level and not much blending action. I suspect the preamp designs are old school using germanium transistors...
  20. Audioguru

    2-channel passive mixer-independent volume control for each pickup

    A preamp with an output impedance that is very high at 3.5k and another preamp with a variable output impedance as high as 10k? VERY weird.
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