Circuit Project Electronic

CMos IC1 and IC2B quad AND gate form a 2.4576 MHz crystal oscillator plus a 2400 times divider. IC3A provides further division by 16, delivering a 64 Hz stable frequency square wave. This frequency is multiplied (by means of Phase Locked Loop IC5, double decade divider IC4 and IC3B 4 bit binary divider) by the [...]

The circuit above is an automatic switch which functions in absence of light. The IC 4060 works as an oscillator and the generated signal is applied to the base of T4 transistor. Phototransistor T3 is in conduction by existance of light and it keeps the T5 transistor’s base at ground potential.
When no light reachs the [...]

Introduction
With this mAh meter you can check the mAh capacitance of your NiCad or NiMH rechargeable batteries
Normally the cheaper NiCad AA-type cells have a capacitance of 500-750mAh (NiCAD) the more expensive
NiMH AA-cells types are up to 1800mAh.
I built this circuit because the capacitance of some of my older NiCad batteries seemed to be quite [...]