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    transformers back to back - why won't work?

    Small power transformers such as that are typically specified for input voltage and output voltage/current. While I did not hear the video mention anything about a current rating, a small transformer might be rated for 2 amperes, so the transformer could drive a 36 watt load at 18 volts while...
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    Assistance with Transistor Theory

    The problem seems to be narrowing and clarifying itself. With that in mind, a warning should be prominently posted for the unsuspecting.
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    Assistance with Transistor Theory

    That is a rather slim ledge to be clinging to. With a good current source, the difference between infinity and not measurable.
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    Assistance with Transistor Theory

    But if you drive the base with a current source, the large resistance becomes a very, very large resistance approaching infinity. A review of Circuits-101 should convince anyone that an infinite resistance is the same as an open circuit. So when driving the BJT with a current source the...
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    Capacitors

    If you have a 0.1 μF ceramic decoupling capacitor, place it in parallel with the 100 μF electrolytic and run the measurement again (especially out past 1 Mhz). It may provide a good demonstration why ceramic capacitors are distributed along the power bus on a PC board.
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    [HELP] - Basic AND gate problem

    Well, it could be 'NO'. Just mark a 'YES' (logical TRUE) on the other side of the switch.
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    [HELP] - Basic AND gate problem

    Look at the input of the 74LS08. It is biased HIGH by the 20K resistor. If the input is left open, the input is HIGH. Unless at least one of the inputs is taken LOW, both inputs are HIGH and the output is HIGH. So if all you have is a SPST switch, the switch must connect the input to GND.
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    Thevenin Equivalent

    The problem shows what amounts to two Thevenin equivalent circuits in parallel driving one load resistor. What if you converted each Thevenin into its Norton equivalent? Simple to do. Then you would have two Norton equivalent circuits in parallel driving one load resistor. Or two current...
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    What steps do i have to take to make an electronic calculator?

    As you see, a calculator is not much more than a keyboard, a display, and a microprocessor. If I were to try building such a calculator using the hobbyist parts I'm familiar with, it would probably end up being the size of a cigar box. However, if I wanted something small, sleek, and slim...
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    bridge rectifier circuit

    Do not ground the AC input, leave it floating. Instead ground Node 1 or Node 2, depending on whether you want positive or negative DC voltage with respect to ground.
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    Why doesn't my shift register work?

    Try shorting out the LED's on the input pins. The voltage drop on the LED may be preventing the input from getting a low enough voltage to be a logical ZERO.
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    help me to design simple buzzer

    http://www.electronics-tutorials.ws/waveforms/astable.html
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    Active filters in parallel

    Not sure what you mean by "measurement of each R1" and how that would give different values from other measurements of R1. Nor can I see how the R1's are in parallel. What I can see is that any level adjustment with one of the 20K potentiometers will change the frequency characteristics of all...
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    electronic cycle counter

    Searched for 'electric totalizing counter 12VDC' and found an example of a counter that might work for you.
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    Assistance with Transistor Theory

    So you were not talking about a BJT, rather the operation of a circuit with an emitter degeneration resistor. Nevermind.
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    Assistance with Transistor Theory

    That would be something really interesting to see! What sort of test circuit would be necessary to demonstrate that collector current controls Vbe?
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    Assistance with Transistor Theory

    Yes, that was my whole point. It is the base current that controls Vbe. The current source provides whatever voltage is necessary for the base to accept that amount of current. That is why the base is biased with current.
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    Assistance with Transistor Theory

    The object of determining the device characteristic is to control the amount of base current. If the base resistor is large enough, the base will behave as though the base circuit is open. How large do you think the base resistor needs to be before the BJT can't tell the difference between the...
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    Assistance with Transistor Theory

    In practice a resistor works well enough and is much cheaper than a good current source. But for making device measurements with constant Ib it is best to use a current source so that Vbe will become its natural value. How else would you get true & accurate device characteristics?
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    Assistance with Transistor Theory

    But that is just so wrong. A current source has infinite resistance, so driving a BJT with a current source is applying an open circuit to the base and forcing the specified current to flow in the base. With a bias resistor there is a circuit, but with a current source the device is fully...
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