Month: September 2013

Debugging a Hot Wires circuit

Jude was given an electronics set for her birthday, called Hot Wires. You connect components together with poppers to make circuits, and it’s generally very good. One of the experiments is called ‘traffic lights’, and is supposed to be a circuit where you choose whether a green light or a red light shines, by pressing a button. Simplifying slightly, its circuit is The LED modules actually have series resistors inside them, so it’s safe to connect them across the battery voltage like that. With the button switch (bottom left) not pressed, only the red LED is supposed to light. If you press the button switch, the red LED is supposed to go out and the green LED light instead. But

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A fruitful exchange with the State Examination Commission

While looking through some past and sample papers to help with some volunteer maths tutoring I do, I came across what I was fairly convinced were errors in a question in a sample paper written by the State Examination Commission. What followed was a very positive exchange of correspondence with the examiner, and the end result is that they are going to review the question. It was refreshing to have such an exchange with a public body, in particular with somebody who directly and properly engaged with my query. If only all interactions with public bodies were as satisfactory. The question The question at issue is Question 1 on paper 2 of their 2012 sample. It reads, in relevant part, The

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