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  1. Audioguru

    need help electronic/relay problem phone horn

    Your measurement of 0.04V across an 8 ohm speaker causes the power of (0.04 squared)/8 ohms= 0.0002W which is 200 micro Watts which can be barely heard. Your meter is probably designed to measure 50Hz or 60Hz from electricity, not the much higher ringing frequency sound produced in the phone...
  2. Audioguru

    need help electronic/relay problem phone horn

    The ringing volume control was set to minimum?
  3. Audioguru

    need help electronic/relay problem phone horn

    Like I said in the other forum, buy some loud ass ringers. Some are loud and some are not.
  4. Audioguru

    Using Detuned AM/FM Radio as Spectrum Analyzer Input

    The parallel LC parts are a certain fairly high impedance at resonance.allowing amplification. Shorting the LCs will produce no amplification and the transistors will produce lots of smoke. Please learn about the basics of electronics.
  5. Audioguru

    Place to purchase sankyo cassette motors

    I have a high quality cassette recorder player but it is an antique now and I have not used it for maybe 30 years. I was working for Philips 58 years ago when they invented the Compact Cassette and I quickly improved its original horrible telephone/AM radio quality to hifi. Then Dolby and Chrome...
  6. Audioguru

    Using Detuned AM/FM Radio as Spectrum Analyzer Input

    A radio has many tuned LC circuits to select only one radio frequency but you want to select very many radio frequencies. Most radios have AGC (automatic gain control) which adjusts the gain for each radio frequency. The radio signal level from an FM radio station is constant. But the radio...
  7. Audioguru

    Why Do DC Inverters Damage Items?

    The name Sunbeam and the logo are the same as the Chinese garbage batteries sold cheaply in "dollar" stores. Poor quality does not last long. But Amazon replaces anything they sell. I wonder how many people return the junk then it is replaced with more of the same junk?
  8. Audioguru

    Replacing NIMH batteries

    My high quality Energizer AAA Ni-MH batteries are rated at 800mAh. The AAA Ni-MH batteries that came in cheap solar garden lights are marked 200mAh but perform like they are only 100mAh.
  9. Audioguru

    It's Been a Long Time.....question

    Welcome back. It is winter and some places on earth get very cold. Your furnace heats the air inside but reduces the humidity that is needed to reduce or eliminate static. A humidifier is used to increase the humidity back to normal and your health will also be better Hey, It gets very cold...
  10. Audioguru

    Connecting a 8 ohm buzzer with a 555 timer

    I wrongly thought the 555 was used as a timer instead of as a power oscillator. Even if a piezo transducer is used as a speaker it will not produce 1kHz. The original article had the fuzzy schematic with its parts too far apart and the 10nF looked like 10uF. The text said when the reset pin...
  11. Audioguru

    Ohms calculations does not match meter reading

    Specs for the meter show a burden resistance of 5 ohms on the 200mA range. The meter leads also add to the resistance. The battery is weak and is almost dead so its power is quickly draining.
  12. Audioguru

    Ohms calculations does not match meter reading

    We told you that the 9V battery cannot produce much current. Its 9V fell on its face to only 2.67V when you loaded it. Then the current became reduced to only 2.7mA because the 9V battery that measured 2.67V was almost dead.
  13. Audioguru

    Ohms calculations does not match meter reading

    A little 9 battery is not made to produce more than 10mA for a few hours. A Super-Heavy-Duty poor quality 9V battery from "over there" cannot produce anything. I have one Name Brand 9V battery that was used in something and is dated by me "Feb/2015". It measures 7.57V with no load but its...
  14. Audioguru

    Connecting a 8 ohm buzzer with a 555 timer

    If a speaker is used instead of a piezo beeper that has its own audio oscillator then the speaker will only "click".
  15. Audioguru

    BC547 transistor

    The decimal point is in the wrong place. (5V - 0.7V)/10k= 0.43mA.
  16. Audioguru

    using bjt amplifier to obtain a current higher than the maximum current an arduino can output

    Simple Ohms law says that for 7.5V into the 46 ohms load then its current is 7.5/46= 163mA. The 163mA in the 300 ohm resistor needs 163mA x 300= 48 9V. Then the supply voltage must be 7.5V + 48.9V= 56.4V plus the 1.8V at the emitter of the transistor = 58.2V. Without the load but with a 9V...
  17. Audioguru

    Why use diodes in this circuit

    We are guessing that M1 is an inductive motor. Hee, hee. Use one hand replacing the diode then tell us high high you jump when the transistor turns off.
  18. Audioguru

    using bjt amplifier to obtain a current higher than the maximum current an arduino can output

    Your original circuit has a voltage divider all the time.
  19. Audioguru

    I want to design a single led to be powered by 4 garden-sized solar cells

    A cheap solar garden light has a small solar panel that produces a low current and a poor quality battery that holds only a small amount of current. Then the LED lights dimly only for a few hours. Instead use a solar garden light with a larger solar panel and with a higher quality battery...
  20. Audioguru

    hand sensor

    C5 will probably prevent radio signals from activating it. It will not work if there is no AC electricity near the human. It will need a 1.2V input signal to begin turning on but needs much more sensitivity to do what you want.
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