A Strobe flasher for bike indicator

Simple circuitry allows the project to be built at low cost in a lightweight, compact

package that can be secured to the bicycle or the rider's belt. 

The light from this circuit uses a xenon tube to generate a bright flash that can be

seen from a great distance - but is not intense enough to destroy a driver's night vision.

Circuit 

Parts Lists

Build your own this low cost analog capacitance meter

When a capacitor is connected to a constant-voltage source through a resistor, the charge on the capacitor increases exponentially. If the source supplies a constant current, however the charge on the capacitor increases linearly. This linear charging principle is used here in the design of capacitance meter which will measure values outside the range of most such meters. 

By using a constant-current source, the meter determines the time it takes to match the charge on the unknown capacitor to a known reference voltage. The meter has five full scale range o 1, 10, 100, 1000, and 10,000 uF.on the 1-uF scale , values as small as 0.01 uF can be read easily.

The Circuit 

 

Power Supply

Parts List

PCB Layout

Component Layout 

Prototype:

source :  Electronic Experimenters Handbook 1980 edition