Zero, right? It has no effect at all. It's really nice stuff. I would never consider using this kind of voltage amplifier without a bootstrap like this.
Though I probably would include an AC gain leg at the emitter, too. Too much good for so little effort. Since this bootstrap circuit is used where an amplifier is required to have a high input impedance as LvW points out , it is often used when the voltage source also has a relatively high source impedance.
So "Vin" is often accompanied by an equivalent Thevenin resistance of significance. There are protection diodes within the LTC that guide input overvoltage currents to either Vp or Vm. When powered, the relay connects the input directly. This can only be safely done if there are two comparators that sense input overvoltage and quickly release the relay. This can be done in 1 ms to 2 ms, allowing a transient mA input current that will not melt the protection diodes of the LTC These supplies probably cannot absorb the overload current since that current is backward to normal supply operation; we would depend on large enough bypass capacitance to hold the supply voltage safely while waiting for the relay switch relief.
When it came time to test the lab prototype, I realized that I had no signal generator with enough output voltage swing of any waveform to exercise the circuit. It is time to come up with an amplifier that can cleanly reproduce waveforms at large amplitudes. Figure 4 shows a high voltage discrete realization of a current-feedback amplifier CFA. CFAs have fabulously high slew rate and, usually, wide bandwidth.
High voltage transistors have higher parasitic capacitances and lower F t s than lower voltage types. Some warnings here. There is no current or dissipation limitation built into the circuit, so heavy sustained load currents more than 10 mA will burn out the output stage and maybe more stages. A short-circuit can cause welding if a big capacitor is used.
I crank the lab supplies up and down by hand to avoid hard turn-ons and turn-offs. Please note that even 50 V can cause enough current through a human to cause heart arrest. CFAs generally have high dc errors and poor settling to high accuracies; the op amp fixes those.
The CFA could have been set to higher gain to unburden the control amplifier further, but then the CFA would lose bandwidth and increase its distortion. Overall gain is set by Rf and Rg and is Ctweak and Ctweak2 work with Rf to remove the phase lag of the CFA from the overall op amp feedback above kHz, enhancing op amp stability.
The overall circuit has a 33 MHz, —3 dB bandwidth but with 8 dB of peaking. At least the 8 dB peak does not have a high Q and ringing damps reasonably fast. The intended kHz signals are reproduced just fine below the peaking frequency.
The distortion at an output of 80 V p-p at kHz measured —82 dBc, dropping to — dBc for outputs of 32 V p-p and less at kHz. For measuring distortion, none of the audio analyzers in our lab can beat —80 dBc at kHz, so we must turn to spectrum analyzers.
How can this ever be accurate enough for our measurements? The good news is that the divider resistors have fairly long thermal time constants, and we expect little actual resistor shift in the middle of kHz cycles. We would ironically see worse distortion at lower frequencies, probably 1 kHz and below. The 80 V p-p signal had to be attenuated anyway because of limited analyzer input range, but it is still too large to get the best spectrum analyzer performance.
Our analyzer can only offer —80 dBc distortion unaided, as a trade-off between its noise swamping the harmonics and large inputs causing additional distortion.
A solution is to place a kHz trap at the analyzer input to kill the fundamental amplitude. With less than a few millivolts of signal harmonics only we can approach — dBc measurement range. Figure 5 shows the test setup. This improves its distortion to about — dBc, lower than the circuits to be measured. The cleaned-up signal is boosted by the high voltage amplifier and passed by the buffer, which drives the divider.
The inductors are constructed of magnet wire wound on large bobbins intended for power E-I cores. Core materials of any kind cannot be used due to added distortions; air-wound is mandatory. You just wind and measure repeatedly. Mostly this mechanism is applied in a common collector emitter follower amplifier. Applications of Voltage shunt feedback amplifier? A transistor can act as an amplifier. An amplifier you use for music might have many transistors as well as many other types of components.
Transistors have other applications as well. A Op-amp has three distinct parts and applications. They are a differential amplifier, a voltage amplifier, and an output amplifier. A class-A amplifier is used to amplify small signals when power use is not an issue.
A instrumentation amplifier is a special purpose linear amplifier used to amplify low level signals. These are used in many industrial and medical applications. A: feedback is not an application but rather is a must to keep a system or amplifier stable in the linear regions. High gain. Class B operated amplifier is used extensively for audio amplifiers that require high power outputs. Its also used as the driver and power amplifier stages of transmitters.
Bootstrap Productions was created in Twitter Bootstrap was created in For other applications speakers usually have a power rating. An amplifier amplifies voltage or current. The most basic amplifier consists of a transistor where a signal is fed into the base and is output to the emitter or collector. For simple, low frequency applications not RF , it may be simpler to use an operational amplifier op amp than designing your own amplifier.
Also, the data sheets provide very helpful schematics for creating an amplifier. A very common one is the ; these are also fairly cheap. His name was William Turner. He went by the name of Bill Turner. His Nickname was "Bootstrap". Most people called him "Bootstrap" or "Bootstrap Bill". Its used in collector amplitude modulation,Radio frequency recievers.. Log in. Electronics Engineering.
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