Kevin Weddle

You might want to test the power supply different ways. A variable high power resistor can be used test the supply under DC conditions. Then a circuit can be made to test at increasing frequency loads. Some common electronics products you generally buy can also be used to test the power supply.

Hero99, are you a moderator?

I must be wrong. But the high power resistors I bought do not have the value I thought they had. Why must high power resistors have a value that are not what they say they are. I pay a lot for these high these things.

Are simply constructed oscillators worse than oscillators used today? If they are, can it proved that the oscillators used today are without a doubt, and with no exception better in every aspect?

An opamp can use a thyristor in it's feedback to limit gain. If the error correcting device is at a high enough frequency to detect an unwanted change in the input signal, the gain can be limited. If your going to use high speed logic devices in a circuit anyways, why not utilize them more?

I don't believe linear control is unreliable. But a signal that is produced by logic control can poroduce a more time sensitive response. Microprocessors generate at the the nanosecond. So as far as audio goes, it's much more of a higher frequency than that. Maybe a high frequency expert can explain as to why a high a frequency circuit can't be used in lower frequency applications.

Most designs employ a large number of components and they generate a lot of noise. But error correction is linear in most cases. If a circuit is going to incorporate a microprocessor, why are smaller circuits limited to simple, linear error correction? A voltage regulator IC, a phase lock loop, an opamp circuit or any other feedback circuit never seems to be logic controlled.

The energy that can be produced from energy sources can be small. Photoelectric cells are being used to produce small amounts of energy, but they produce enough power to power low power devices.

I think your right, but there are two problems. The incoming signal, let's say centered at 100MHz will not exactly match the oscillator. So the resulting frequency won't be 0Hz. The bandwidth of the incoming signal will result in frequencies maybe to 1MHz. So you could lose something, maybe not. The problem is that if you set the oscillator at let's say 95MHz, a 95MHz transmission from another station will appear at the lower end of the spectrum, only slighty diminished assuming the correct length of antenna. High pass filtering stages would reduce this unwanted station.

An 80A pulse width modulator is too high of amperage for any that I've seen. I'm sure your refering to high voltage and a low impedance. But either way it's going to be a larger circuit. Logic devices and reactive components are used to produce the initial PWM signal

The capacitors have to be able to deliver the required voltage to the load, which requires a capacitance that will charge to the voltage within the charge time and maintain the voltage until the next charging time.

Higher or lower? The oscillator should match the incoming frequency as close as possible. Otherwise, your introducing a different frequency, which results in something more indicernable. Fortunately, most broadcasts have plenty of power and a wide enough bandwidth for audio and video.

I was refering more to passive component circuits involving crystals, ceramic filters, SAW filters and other technologies. And, aren't the passive components available today more capable of producing the desired filter response?

Hero99, there are a variety of filters available. Many designs use only LC filtering, but is it because other types of filters do not have the requirements to meet the design? Many filters have great response, but a narrow specification and might be intended for only a few applications.

The voltage rating of a capacitor is proportionate to the value. The construction of high value capacitors results in more tolerance than lower value capacitors.

What is the limitation of using filters that have better attenuation than capacitor and inductor filters?

Another way to design the circuit might be to use a 3 amp NPN in series with the battery, and a 200mA PNP transistor in series with it's base to get a constant source of current to the battery.

I'm sorry, the circuit looks good. The 3.3 ohm resistor isn't power efficient, but maybe it can be replaced with a circuit.

I misread the original circuit. But I don't think a 200mohm resistor would see a voltage drop, unless it's a high capacity battery.

The original circuit posted seems to operate by switching on/off rapidly. Is that how it's operating?

Phase shift oscillators produce 180 degrees phase shift using cascaded RC stages. Maybe the components are chosen so that each stage is independent of the other and reduces the loading effect, which would keep the phase shift at 90 degrees at best.

Low current biasing seems like a problem also. It only takes 200 mV before a transistor goes into cutoff. I have made simple cirucits that are just DC biased only, and have watched the DC bias drift by 200mV. But my test lab uses 7805 and 7812 voltage regulators and they're used, and so were the components in the circuit. Test labs are general purpose, allowing for a variety of loads.

Doesn't the top MOSFET receive a larger signal than the bottom MOSFET? They operate in parallel, but have inputs of different magnitude, and outputs of different magnitude. This means that the MOSFET's can be damaged easily if the circuit isn't built right with new components.

A zener diode has low output impedance, like a battery, so you have said before. But even being a shunt regulator, the voltage isn't good enough to act as a voltage regulator. Otherwise a simpler circuit using zener diodes would substitute for a voltage regulator, with a little waste of power.

My mistake. Zener diodes are for voltage reference. The reason that they do not take the place of a voltage regulator is because their voltage isn't stable enough to accurately regulate a changing load.