Talk:Bootstrapping (electronics)

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Unenergised Alternators

"if the battery is totally flat the alternator won't produce any output voltage to spark the plugs or recharge the battery (by push starting for example) since it will be unable to bootstrap itself. However, in practice, a battery will usually have enough residual charge to avoid this."

This isnt entirely accurate. What happens is some residual magnetism in the alternator causes it to generate a little output, which is fed to the field coils, thus increasing the mag field... so outpout increases etc. its a bootstrap process.

Its a bit more complicated as what happens in practice depends on whether a battery is connected, the state of the battery, and alternator details etc. Tabby 14:07, 10 September 2007 (UTC)[reply]

to explain....

"In a typical car alternator, a DC field current is required before the device can produce any output. Once running, a small portion of the output is fed back to keep the field alive — this can be seen as a form of bootstrapping. The initial priming current is usually obtained from the vehicle's battery — if the battery is totally flat the alternator won't produce any output voltage to spark the plugs or recharge the battery (by push starting for example) since it will be unable to bootstrap itself. However, in practice, a battery will usually have enough residual charge to avoid this."

Often quoted but wrong. Car alternators fire up just fine with no battery. The iron in car alternators is left after use with some residual magnetism, and with this alone the alternator will produce some output, even if not 12v. The reduced output is fed to the field windings, increasing mag field, and increasing the main terminal output. This bootstrapping process produces the full rated output in under a second.

If a car battery is flat it will short any main terminal output, preventing any field build up, thus the process never gets off the ground. If you dont mind a big risk to your car's electrical system, disconnecting the battery will get such vehicles started. You gotta push it faster than with a full battery though. Once running the battery is reconected, otherwise serious damage to the electrical system is very likely due to load dump with an inductive generator. Tabby (talk) 16:53, 31 March 2008 (UTC)[reply]

Computing

Why is the computing section here? there is another article for this topic —Preceding unsigned comment added by 24.23.251.217 (talk) 04:50, 28 March 2008 (UTC)[reply]

What is the basic idea of bootstrapping?

Johnuniq, I will explain thoroughly what bootstrapping is but I would like you first to make yourself familiar with Miller theorem and, in particular, with virtual infinite impedance. Circuit dreamer (talk, contribs, email) 08:13, 29 April 2011 (UTC)[reply]

Bootstrap circuit example

It would be great to extend this article using information from following application node: https://www.fairchildsemi.com/application-notes/AN/AN-6076.pdf