Dynamic Mic Amplifier (To Use Speaker as Microphone)

This is the circuit diagram of dynamic mic amplifier. This simple and easy built circuit can be used as a subtitute of an electret microphone. It will turn an ordinary mini speaker to become a pretty sensitive microphone.

Basic Oscillator Circuit using Two Transistors

This is the schematic diagram of basic oscillator circuit which using two transistors. When two transistors and a couple of passive components are connected as shown in the figure, the circuit starts to oscillate. The frequency of oscillation can be adjusted by changing the values of either the resistor or the capacitor.

One Transistor LED Flasher Circuit

Here the schematic diagram of one transistor LED flasher. This circuit can be the simplest circuit led flasher over the world.... :D

This is a novel flasher circuit working with a single driver transistor that will take its flash-rate from a flashing LED. The flasher in the photo is 3mm. An ordinary LED is not going to work. The flash rate are not able to be altered by the brightness of the high-bright white LED can be adjusted by replacing the 1k resistor across the 100uF electrolytic to 4k7 or 10k.

Magic Lights Circuit using Bi-Colour LED

This is the magic lights circuit which use bi-colour LED as the output to provide the light. The circuit uses 14 bi-colour (red and green) LEDs having 3 terminals each. Various dancing colour patterns are generated utilizing this circuit considering that each LED can create three various colours. The middle terminal (pin 2) of the LEDs will be the common cathode pin that is grounded. When a positive voltage is applied to pin one, it emits red light. Similarly, when positive voltage is applied to pin 3. it emits green light. And when positive voltage is simultaneously applied to its pins 1 and 3, it emits amber light.