eJournal for teachers of electronics and communication technology
Like many essential ideas in electronics, voltage is a slippery customer; it’s easy to think you have a grip on it only to find that, when you think a bit harder about it, you don’t after all. However all is not lost; you can do a lot of useful things in electronics without holding a fully formed theory of voltage. […]
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In this second and final part of our look at voltage, we explore what an electric potential actually is and how a voltage (potential difference) can be created. PREFACE Part 1 of this article on voltage introduced the following key ideas: • A signal in a system is a voltage • A voltage is a difference in electric potential between […]
Continue reading »In the MOSFET, the gate is isolated from the conducting channel by a thin insulating layer (as indicated by the symbol). This forms a capacitor which can be used as the timing capacitance. As with all capacitors, the gate capacitance also has a leakage current. For the ZVN4206A the gate capacitance is typically 300pF and the leakage current 1nA. The […]
Continue reading »It is difficult to achieve timing delays of more than a few minutes with the standard 555 circuit because of the way electrolytic capacitors behave. When the capacitor plates are charged a small current passes through the dielectric – this is called the leakage current. A real capacitor behaves like a perfect capacitor in parallel with a leakage resistance. To […]
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