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  1. audioguru2

    RC-(remote controlled) Car

    The article tells you. The power supply voltage and current are low, so resistors will not get hot. The emitter resistor will have about 1V max across it and 100mA max in it which is only 0.1W. The article shows how they shielded theirs. I have never seen an opamp with such high gain-bandwidth...
  2. audioguru2

    Datasheet Archives

    To get datasheets, I use www.datasheetarchive.com .
  3. audioguru2

    12 V DC to a 220V AC Inverter AMplfier Design

    Every one that I have seen. It is part of how they are made. It is a very powerful zener diode so it is slow. For high speeds, a quicker diode is added. Pins 10 and 11 are 50Hz opposite each other (one is high while the other is low). Pin 13 is 100Hz. Of course the max voltage rating matters. In...
  4. audioguru2

    motor driver L298 help

    MP. You can vary the width of TTL or Cmos pulses, or keep the "on" time of the pulses the same and vary the speed of the pulse stream as you say, to change their duty-cycle for PWM. I hope you don't mean to change the speed of the oscillator as in our project that doesn't work...
  5. audioguru2

    Current Sink for LEDs

    If you connect a single 2.3V LED in series with a 47 ohm resistor and across a 5V supply then the current will be 57.4mA and the LED (rated max is 30mA) will burn out. It will be very bright for a few milli-seconds. The resistor's value must be recalculated for just one.
  6. audioguru2

    Current Sink for LEDs

    Yeah, with only 5V for the supply, two 3.5V blue or white LEDs in series wouldn't be very bright. ;D My red LEDs are only 1.8V and they would be fine with two in series.
  7. audioguru2

    motor driver L298 help

    Of course not. The ICs are just switches. I said that PWM is needed for speed control. It is shown in Texas Instruments datasheet for their L298. Rod did not understand about PWM for the speed control that he needs so I explained it to him.
  8. audioguru2

    DIY WBO2

    Make the circuit like on the schematic and it might work. I have seen many schematics and parts lists on the internet with errors. Even errors on pcb wiring.
  9. audioguru2

    Audioguru FM Tx

    I tested my transmitter with a new 9V alkaline battery and it went far. After about 1 hour the voltage was about 8V and the range was less. It should have more power output with an 11V supply but I don't know how much. The output transistor might be OK or might get too hot and melt. The drive...
  10. audioguru2

    Data Transmission using Xmitters

    Hi Ante, If you are far from the telco's central office then the high capacitance of the telephone line cuts the high frequencies. My daughter's ADSL is only about 40kb/s which is better than 8kb/s from a 56k modem on the same phone line, but not nearly as fast as yours. I switched my high...
  11. audioguru2

    DIY WBO2

    Sorry, the circuit doesn't need a negative supply, it makes its own. The power supply for the circuit is very confusing: 1) JP12 I guess is the car's ground but the circuit calls it "-5V". 2) I guess the voltage regulator is a 7810, and the circuit calls its output "+5V" instead of +10V. 3)...
  12. audioguru2

    Battery current

    Batteries have different chemistries. Some are cheap and perform poorly (carbon-zinc) but others are expensive and perform better (alkaline). Which one? Battery cells have many different sizes. The tiny ones can't supply much current. Go to www.energizer.com and click on Technical Info at the...
  13. audioguru2

    RC Car

    A bigger motor won't fit. The battery would also need to have more voltage and more current and also wouldn't fit. The electronics and wiring that drives the motor would also need to be re-made to pass the higher current. Then the car would be so heavy that it might not go fast. Of course the...
  14. audioguru2

    12 V DC to a 220V AC Inverter AMplfier Design

    They are to protect against reverse-voltage spikes. But Mosfets already have diodes in them which is how they are made so I wouldn't add the 1N5408 diodes. Look at the diodes (zener diodes) in an IRF540 Mosfet. That would cause smoke. When one side of the center-tapped transformer winding is...
  15. audioguru2

    rechargeable battries

    My hard drive is full of handling articles of Lithium rechargable batteries but I haven't selected the best article. I downloaded the good Ni-Cad and Ni-MH Applications Manuals from Energizer which are attached. The most important thing to increase their life is to not overcharge them...
  16. audioguru2

    RC-(remote controlled) Car

    Hi Faizan, The original project has its oscillator separate and shielded from its RF amplifier but your layout doesn't. You will need to add emitter resistors to the output transistors when you change them to RF types, as is explained in the article.
  17. audioguru2

    RC Car

    He says to take a brand new motor and runit slowly with a 3V supply and cooly for 2 hours. He says then the brushes will make better contact, the bearings will have less friction and  make the motor more powerful. I doubt that you would notice any difference.
  18. audioguru2

    RC Car

    A 1800mA/hr battery's charge will last 2.4 times longer than a 750ma/hr battery's charge. The cheap little motor will burn out 2.4 times sooner if you run it at max speed all the time.
  19. audioguru2

    SCR Question

    Hi Sundin, You are correct! ;D
  20. audioguru2

    RC-(remote controlled) Car

    Hi Faizan, Doesn't your country have rules and regulations about radio transmitters like most countries? Here the broadcast bands are full and a complaint about interference makes the RF cops find the cause of the interference then go after the person responsible. There are certain other...
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