Project 139 electricity you can walk away with – Elenco Snap Circuits Motion User Manual

Page 69

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Project 139

Electricity You Can

Walk Away With

This circuit has two parts; build it as shown, but initially place the 100mF

capacitor (C4) across points A & B. Then pick up C4 and place it across

points C & D; the red/yellow bicolor LED (D10) flashes. Move C4

between points A/B & C/D several times.
In either location, C4 may be oriented in either direction, but its direction

determines the color of the LED flash.
You can replace the 100mF capacitor with the smaller 1mF capacitor

(C7), but the LED flash will be much dimmer.

Placing the capacitor across points A & B charges it

up, and placing it across points C & D discharges it

through the LED. Once charged, capacitors hold their

charge well - you can charge up the capacitor, walk

away with it for a while, then use it to light the LED.
Despite the “+” marking, connecting your capacitors

backwards across your batteries in this circuit will not

harm them.

Project 140

Electricity You Can

Walk Away With (II)

Modify the preceding circuit to match this one. It works the same way,

except the adjustable resistor (RV2) slows down the capacitor

discharge, making the LED dimmer but stay on longer. Try this at

different RV2 settings.

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