Flip - Flop Circuit of Two LEDs

       Click here to see the circuit on Multisim Electronic Workbench software

       This circuit is simply two identical circuits. Each one consists of a LED, 390Ω resistor, 10KΩ resistor, 10µF capacitor, and NPN BC 547 transistor which acts as a switch. The circuit as a whole works on 9V Battery.

       The switching frequency of the circuit depends on the capacitance of its capacitors. In fact, the switching frequency is inversely proportional to the capacitance, and you can see this by changing the values of the capacitors through the Multisim simulation.

       By: Mohammed M. Mahmood

Simple Touch Circuit

This circuit demonstrates the action of transistors.
The current passing through my fingers to my body is amplified by the NPN BC 547 transistor and becomes sufficient to illuminate the red LED.
In the first case, only one transistor is used. While in the second case two transistors of the same type is used. So the amplification in the second case is twice that of the first one, the thing that makes the red LED illuminates brighter and just by a slight touch.

By: Mohammed M. Mahmood

A Simple Circuit

Two LEDs Flip-Flop Circuit

Click here to see the circuit on Multisim Electronic Workbench

The two transistors in this circuit work as switches.