3 ms·

It's a bit more fundamental than that. A FET goes between say, 0.01 Ohms and 1,000,000 Ohms for fully on and fully off. The times in between are where it pass

It's a bit more fundamental than that. A FET goes between say, 0.01 Ohms and 1,000,000 Ohms for fully on and fully off. The times in between are where it passes the most power through it and that's because of how Ohms law and Power being current times voltage (ignoring differing phase between current and voltage in AC circuits). This all still remains true even for the memristors. You can do analog stuff with higher resistance and lower currents, but then you end up more susceptible to noise and other randomness induced by the environment: thermal noise, electric noise, magnetic noise, and RF noise (technically also electric noise, but more organized), etc. All that being said, for a NN this might actually be somewhat acceptable, but for general analog circuitry you can't get past this problem at all. That's a large reason why most analog circuitry these days does as much as possible in a digital domain before converting back to analog, even simple amplification. A class D amplifier does the whole job by chopping up a large voltage into just on and off and then filters it afterwards. Even though you have power loss in the filtering, the end result is much easier to have stable, and get the desired amplification. You still find class A and B amplifiers where the high frequency chopping noise isn't possible to filter out or would cause other problems, particularly when you look at RF circuitry since you'd end up transmitting that high frequency noise and causing other problems for yourself.

sgtnoodle 6y ago
It's my understanding that, to some extent, nerves and muscles operate with hysteresis based on charge thresholds, and rely on pulse-density encoding for variability rather than proportional voltage or current modulation. Presumably, that seems to be why your muscles shake when under heavy strain. It sorta makes sense, considering your body is generally electrically conductive everywhere. Signals propagate as waves of charge sustained by cells opening and closing little pores that selectively release ions. "Conductors" have pores, and "insulators" don't. That's also why nerve signals are relatively slow to propagate vs. straight up electricity. That's also why you can measure muscle activity via an ECG; you're measuring the transient voltages being generated by the waves of charge moving around. The voltages themselves don't have much meaning to your body. Of course, if you apply enough voltage to build up a charge inside a muscle, you can cause it to actuate. I recently had to get a pacemaker, and apparently the particular lower threshold to trigger my heart muscle to contract is around 0.7V for 350uS, at whatever impedance the lead happens to be. Below that, and my heart muscle does nothing. Anything above that, any my heart muscle does a full beat. The device applies a 2V pulse so that there's plenty of margin, and can go up to 5V if needed, in case the lead's impedance increases. The lower the voltage the better, in terms of battery life. The cool thing is that the device can safely coexist with any natural electrical activity my faulty nerves may have, since the muscle simply responds to whichever pulse happens to arrive first.

sgtnoodle 6y ago

It's my understanding that, to some extent, nerves and muscles operate with hysteresis based on charge thresholds, and rely on pulse-density encoding for variability rather than proportional voltage or current modulation. Presumably, that seems to be why your muscles shake when under heavy strain. It sorta makes sense, considering your body is generally electrically conductive everywhere. Signals propagate as waves of charge sustained by cells opening and closing little pores that selectively release ions. "Conductors" have pores, and "insulators" don't. That's also why nerve signals are relatively slow to propagate vs. straight up electricity. That's also why you can measure muscle activity via an ECG; you're measuring the transient voltages being generated by the waves of charge moving around. The voltages themselves don't have much meaning to your body. Of course, if you apply enough voltage to build up a charge inside a muscle, you can cause it to actuate. I recently had to get a pacemaker, and apparently the particular lower threshold to trigger my heart muscle to contract is around 0.7V for 350uS, at whatever impedance the lead happens to be. Below that, and my heart muscle does nothing. Anything above that, any my heart muscle does a full beat. The device applies a 2V pulse so that there's plenty of margin, and can go up to 5V if needed, in case the lead's impedance increases. The lower the voltage the better, in terms of battery life. The cool thing is that the device can safely coexist with any natural electrical activity my faulty nerves may have, since the muscle simply responds to whichever pulse happens to arrive first.