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  1. audioguru2

    Amplification and loss

    An amplifier has gain, not loss. You can reduce the gain with negative feedback or reduce the input and output with a volume control at the input. If you need to reduce a signal after amplifying it then the input level is too high or the amplifier's gain is too high. If your amplifier causes...
  2. audioguru2

    Will this high-current regulator work?

    The PNP transistor has nearly 9.8V across it and 4.75A through it. Then it heats with 46.55W which is a lot of heat to throw away and it will be difficult to cool the transistor.
  3. audioguru2

    AC-DC Inverter Circuit Principles

    A modified sine-wave is really a modified square-wave. The wave goes to a positive peak then to 0V for a pause then to a negative peak then to 0V for a pause again over and over. The wave is produced with pulse-width-modulation so that voltage regulation can be achieved. One group of Mosfets...
  4. audioguru2

    opamp roll-off

    You make no sense. The datasheet shows that the voltage gain of a lousy old 741 opamp is only about 8 at 100kHz, not 100. The filter capacitor is built inside the opamp (not external) to prevent it from oscillating when its phase-shift causes 180 degrees delay. The capacitor causes a roll-off so...
  5. audioguru2

    Electrolytic Capacitor

    Cheap speakers use non-polarized electrolytic capacitors in their passive crossover network to keep the low frequencies out of the tweeters and keep the high frequencies out of the woofer. Inexpensive audio amplifiers use them to couple audio frequencies.
  6. audioguru2

    0-30V Stabilized Power Supply

    Something is wrong in the U3/R7 circuit. No. A 1N4734A zener diode is rated at 500mW. But its voltage is rated when the current is 45mA which is much too high. It might not regulate when its current is only 1.5mA or 5.6mA. 1N752A and 1N5232B zener diodes are also rated at 500mW. But their...
  7. audioguru2

    0-30V Stabilized Power Supply

    The voltage setting pot should feed 0V to 11.2V to U2. If it is 0V but the output of the supply is 17V then maybe Q2 or Q4 have their pins mixed up and are acting like a zener diode. U3 is the current regulator that is supposed to act like a switch. when it does not regulate current then the LED...
  8. audioguru2

    Electrolytic Capacitor

    Hi Walid, Welcome back. :) An electrolytic capacitor conducts a high DC current when it is connected with backwards polarity. I think the current causes the electrolyte to quickly get hot and boil which makes steam and an explosion.
  9. audioguru2

    Static electricity eleminator

    Low humidity in the air increases the occurance of static electricity. The air becomes dry due to heating the home or business in winter. The air is more humid in summer causing very little static electricity so add some humidity in winter with a humidifier. Grounding the plastic mat will do...
  10. audioguru2

    Equation for Draw on battery by electronic devices

    The 5V/1.2A supply probably charges the battery plus runs the PSP device. It doesn't charge the battery when it is fully charged so then the current is much less. A device does not "accept" all the current that is available, it uses only as much as it needs. For example, a little 7W nightlight...
  11. audioguru2

    Equation for Draw on battery by electronic devices

    If the PSP is just a simple resistor then you can calculate its current at different voltages. But it is a complicated circuit and you don't know its average current at any battery voltage from 4.2V to 3.0V for the lithium-ion battery cell. You don't know if its voltage regulator is linear and...
  12. audioguru2

    40174 & 555 timer

    Hello again, Your circuit is still missing the supply bypass capacitors and CLEAR-not pin connection that were discussed on the other website. The supply bypass capacitors are very important if you use a weak little 9V battery and a high power 555 since the 555 causes a 400mA current spike each...
  13. audioguru2

    Equation for Draw on battery by electronic devices

    Your battery is only 3.6V but your circuit needs 5V. Enough said.
  14. audioguru2

    0-30V Stabilized Power Supply

    10uf/20%/100V is fine but a 50V or 63V capacitor will also be fine, will be smaller and cost less.
  15. audioguru2

    0-30V Stabilized Power Supply

    Make sure that the output of P1 goes down to 0V. The max offset voltage of the TLE2141 is only 1.4mV for the inexpensive one and the circuit amplifies it 3 times to only 4.2mV. RV1 adjusts the output from negative 30mV to positive 30mV so the null should be 0.00V. Like I said earlier, if the...
  16. audioguru2

    0-30V Stabilized Power Supply

    60W/12V= 5A. So the current regulator reduces the output voltage so that the current is 5.0A. The warning LED should turn on to warn you that the current regulator is reducing the voltage. Maybe opamp U2 is damaged from having its supply voltage too high for it. The opamp is clipping with its...
  17. audioguru2

    0-30V Stabilized Power Supply

    In addition to the errors of the offset adjustment, the opamps are operating at supply voltages above their absolute maximum allowed voltage, the transformer and many resistors are overloaded at full output, the tiny Q2 transistor and single 2N3055 transistor are very much overloaded when the...
  18. audioguru2

    0-30V Stabilized Power Supply

    The original version uses a TL081 opamp as U2 and has the value of R10 completely wrong and it is connected to the wrong voltage.
  19. audioguru2

    Downed Model Locator( it is buzzing too low)

    The loudness of the beeper is determined by its quality (RadioShack parts have very low quality) and the voltage that powers it. Its sound output hole should not be covered.
  20. audioguru2

    Need help!

    It has a very low output power so its range is not far. Maybe across a street. It is tuned with voltage so it needs a voltage regulator. It is missing pre-emphasis (treble boost) like all FM radio stations have so it will sound muffled on an FM radio. It is mono, not stereo.
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