Eco nightlight (0)
01/11/11 •
The nightlight is a popular project in schools and, depending on the circuit used, suitable for a very wide student age range. Even at key stage 2, students can learn much from a basic circuit comprising a battery, switch and LED. More sophisticated automatic PIC or RC timer controlled circuits offer the scope for programming [...]
Recent Posts
The Nightlight – evolution of a key stage 3 project (Comments Off)
24/12/10 •
The When I reached secondary school at the age of 11, the very first project I made in Technology (woodwork as it was then called) was a table lamp based on a halving joint. When I arrived at my present place of work, I was amazed to find that similar projects were still being made! [...]
ZVN4206A N-Channel MOSFET (Comments Off)
24/12/10 •
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 [...]
Long time delays – why they are difficult to achieve with just RC networks (Comments Off)
24/12/10 •
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 [...]
555 timers, who needs them? (2)
26/4/10 •
The NE555 timer first appeared in 1971. Although it is now nearly 40 years old, many exam boards still include it in their specifications. This seems rather odd in a fast developing subject such as electronics. With an ever expanding range of new technology and devices to learn about, perhaps it is now time to [...]
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01/11/11 •
Eco nightlight24/12/10 •
The Nightlight – evolution of a key stage 3 project
