10 Dancing LEDs

This is the circuit diagram of dancing LEDs which consists of 10 units LEDs. The 10 dancing LEDs circuit works like a audio level meter. The LEDs will be dance sequence with the sound level that entering the microphone. Components list: R1_____________10K 1/4W Resistor R2,R3__________47K 1/4W Resistors R4______________1K 1/4W Resistor R5,R6,R7______100K 1/4W Resistors R8____________820R 1/4W… Read More »

Dual Output Stabilized Power Supply

This is a dual regulated and stabilized power supply, usually used to supply amplifier circuit, it also known as split powersupply. There are 3 output that are (+) voltage, (0) Ground (normal), and (-) voltage. The current output max about 0.3-0.5 A. For higher current output, power transistor is needed. Please take a note that… Read More »

Ultrasonic Sensor Switch

Here is the circuit diagram of ultrasonic sensor switch. There are many methods of wireless switching such as by using infrared, AM/FM signal, bluetooth, etc. This is an alternate wireless switching by using ultrasonic sensor. The distance of switching range should be more than 10 meters. This circuit produces and transmits ultrasonic sound of frequency… Read More »

100 Watt Inverter 12VDC to 220VAC with Mosfet

This is another 100 watt inverter circuit diagram. Built based on IC CD4047 and Mosfet IRF540, this inverter have ability to supply electronic device -which require 220VAC- up to 100w from 2-3A transformer from 12V lead acid battery. In the circuit diagram we can observe that 12V battery is connecter to the diode LED and… Read More »

300Watt Inverter DC 24V to AC 220V

This is the 300W inverter circuit which capable to convert 24VDC become 220VAC. With this circuit, you will have 220V AC power with 300W max rated, from 24V lead acid battery or accumulator. Schematic diagram: PCB layout and component placement:

50 Watt Power Audio Amplifier

Here the circuit diagram of 50W power amplifier. The amplifier uses a pair of power transistors that are MJ2955 and 2N3055 to amplify the input signal. You must use a heatsink on those transistors. The below design diagram uses for single input/output channel, just built two similar circuit to make it dual channel (stereo). Schematic… Read More »

Analog Flip-Flop

Here the analog flip-flop circuit which built based on 2 transistors work as switch. This is very easy made and very cheap circuit. You can use this circuit as “the first project” for your students… 🙂 and the result should be like this:

Mini AM Transmitter

This is the simple and low cost AM transmitter schematic diagram built using transistor BC109C. The circuit is in two halfs, an audio amplifier and an RF oscillator. The oscillator is built around Q1 and associated components. The tank circuit L1 and VC1 is tunable from about 500kHz to 1600KHz. These components can be used… Read More »


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