Push to ON and OFF latching Circuit

    Here we can make load ON and OFF using push switches or in a low voltages. using relay in Q1s collector we can control any load with isolation. here me added 5.1V zener to avoid leakage currents that will make the circuit ON when power is ON. current flows through the circuit only when we made ON. so standby current is negligible.

Simple LED Emergency Light

This is simple to make and low cost emergency light. also it gives better backup more than 3 Hour.
low cost and simplicity comes by replacing the battery charger circuit with a any mobile charger, here the connector CN1 must be socket of any mobile charger here me used nokia's charger pin convertor.
  
   The output voltage of most of mobiles will be in 5-7 Volts thus it is suitable for 4.8V batteries. LED D5 acts as charging indicator. while connecting LEDs in parallel all must be same type (same batch).

 

LED Flasher with one transistor

    his is a novel flasher circuit using a single driver transistor that takes its flash-rate from a flashing LED. The flasher in the photo is 3mm. An ordinary LED will not work.


The flash rate cannot be altered by the brightness of the high-bright white LED can be adjusted by altering the 1k resistor across the 100u electrolytic to 4k7 or 10k.

The 1k resistor discharges the 100u so that when the transistor turns on, the charging current into the 100u illuminates the white LED.

If a 10k discharge resistor is used, the 100u is not fully discharged and the LED does not flash as bright.

All the parts in the photo are in the same places as in the circuit diagram to make it easy to see how the parts are connected.

1.5 to a 9V convertor

This very clever circuit will convert 1.5v to 9v to take the place of those expensive 9v batteries.


But the clever part is the voltage regulating section. It reduces the current to less than 10mA when no current is being drawn from the output. You can use two or three old cells for the supply and the circuit will totally use up all the energy from the cells. It's a great circuit for using up those old cells. With a 470R load, the output current is 20mA and the voltage drop is less than 10mV. It is best to use 3 old cells as this will deliver about 2.5v to 3v and the circuit will produce an efficiency of about 70%. Adjust the 15k resistor for 9v.

UNDERSTANDING WORKING

To understand electronics we must work with circuits. electronics lying in circuits or all of its applications are coming through circuits.

CIRCUITS FOR ALL

This blog is for studying electronics via simple circuits.