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Kevin Weddle
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Posts posted by Kevin Weddle
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Could pulse postition modulation more accurately describe the circuit. The filter type circuit following the output transformer cannot be very simple and will reduce power transfer. A square wave will not be output by a transformer but for a short time of the voltage transistion. Also, the voltage that is transfered will be reduced by the same magnitude on the next transistion.
The modified sine wave shown in textbooks is only two square pulses, making it a modified sine wave. -
Good modern inverters use a Pulse-Width-Modulation circuit to synthesize a pure sine-wave by switching at a high frequency.
Or pulse amplitude modulation. I doubt using circuit components after the output transformer because of the high voltage and power transfer problems. So the output of a good inverter is still only compatible with simple electronic loads. -
The simple schematic for a pure sine wave inverter has acceptable efficiency. It looks to be about 80%.
The same basic circuit is used for a modified sine wave inverter. But there is no voltage output from the transformer most of the time. It would seem better to filter or clamp the output, but it would have poor power transfer or still not be a sine wave.
A pure sine wave inverter might be a little inefficient, but the modified sine wave inverter of the same basic design is not a legitimate power supply. A well designed modified sine wave inverter would need to be purchased. -
Fermi level and energy bands have to play small roles. Current value is regardless of valence bands or conduction bands or the energy required. The reason is because energy levels applied to conductors and semiconductors are very high. Electrons can move to any energy level with a change in temperature.
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The reverse diode, I'm guessing, could be an indication of polarity. In a DE MOSFET, 0 Vgs provides better conduction at the source than at the drain with the intended Vds polarity. An opposite polarity Vds apparently conducts better. Sometimes doped silicon pieces are used for electrical contacts.
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Rg needs to be connected to a positive voltage. This is done with two series resistors connected to the +9v supply.
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If the load is a high impedance FET, then it can be done more easily. If the load is low impedance, you should change the circuit which generates the pulse. Is the load a high impedance?
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Yes. You might try using an inverter square wave oscillator as the other input to the XOR. It is a simple enough circuit to fine tune the DPLL. Or you may need a more stabile oscillator. The CD4007 square oscillator Hero99 posted is not a design I'm familiar with, though it may oscillate. The circuit I'm familiar with uses a biased series RC in parallel with the output inverter's input.
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The CD4047 VCO schematic is missing a ground or Vdd compared to a typical square wave oscillator. Does it oscillate?
Klug, how are using the phase comparator? The control voltage pin of the 555 needs to be analog.
A simple analog phase comparator with a crystal generated sinewave input is common. The output of the 555 timer can be low pass filtered before being input to the phase comparator.
The feedback circuit needs to allow for amplitude adjustment and isolation of the 555 output. -
Most PLL's are sinusoidal and their VCO's analog. A 555 timer is a logic device with a discharge transistor, level setting resistors, and a capacitor. It only produces a variable time pulse width.
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That is how it is described to function. The 555 timer VCO is only part of a PLL. The control voltage directly affects the threshold voltage and indirectly affects the trigger voltage. Increasing the threshold voltage creates a wider pulse which is a reduced frequency.
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A high current push-pull amplifier at the output will produce sound from a high impedance speaker, but the amplitude will be low. A higher voltage supply will allow for greater amplitude, and adding transistor amplifier stages will produce greater amplitude. The input input impedance to the amplifier can be increased with higher input impedance transistors.
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You could use these devices for a bridge rectifier or full-wave rectifier if they have P channel and N channel MOSFET's. However they might not be as accurate since the output of a
full-wave rectifier is not regulated. These MOSFET diodes regulate Vds in response to a change in current. -
If Vout is the regulated output, then these are the changes to the design. The rest of the circuit might be okay.
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Okay, if J2 is the output, then Q1 needs to be an NPN and Q3 a PNP. The emitters are then connected to
Vout.
Q2 needs to be a PNP, Q4 an NPN, and their emitters not at ground, but V+ and V- respectively. -
seanacais, is the unregulated voltage connected to J1 or J2. Are you using the corrrect transistors for Q1 and Q3? They are the same transistor, except one is an NPN the other a PNP.
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Assuming you have replaced all of the opamps, the uneven voltage distribution seems very even. Since the circuit is designed by yourself, it may easily be the wrong offset voltages of any of the opamps, and the voltage distribution only looks to be half. A saturated opamp is easy to identify.
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Lower beta transistors used for power applications have low value emitter resistors. Since it is difficult to use low value base biasing resistors, because of loading, the base current may be 1/3 the current of the biasing resistors. So the voltage gain is lower than the collector resistor divided by the emitter resistor.
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If the opamp is used as the output stage of a pulse width modulated signal, then the motor will be controlled by pulse width modulation. However, since that opamp can drive lower impedance loads, it might be possible to simply add a push pull amplifier.
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Hello gogo2520. I have read that microcontrollers can be programmed in C with compilers adapted for certain microcontrollers. Doesn't that make it easier to create larger and almost as efficient microcontroller programs. I know of other languages that can be used, but they would not be as efficient for programing a microcontroller.
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It shouldn't have any effect on the circuit. But I'll guess some loads can afffect the voltage. And also it mostly assumed the load changes the impedance not affecting the voltage source.
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The circuit is a basis for a voltage regulator. But voltage output will not be as it is set to be. The voltage regulation can be improved with an output capacitor.
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The circuit looks okay. But use normal power supply diodes because the average current could be too high for some diodes. You can estimate the amount of average current, but any power supply diode will be good enough that circuit.
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There is a polarity switch S1. It may also need a variable resistor circuit so the user can have an adjustment depending on the type and intensity of outside noise.
inverter
in Power Electronics
Posted
So then a good inverter is two pulses followed by a simple filter? If there are many pulses used to comprise a single sine wave cycle, as I would assume the intention of the design to be, the negative transistions of the pulse will negate the positive transistions unless there were more than a simple LC filter.