A Hierachical Priority Encoder

The above diagram is a hierachical priority encoder circuit. Described on wikipedia, priority encoder is a electronic circuit or algorithm that compresses multiple binary inputs into a smaller number of outputs. The output of a priority encoder is the binary representation of the ordinal number starting from zero of the most significant input bit. They… Read More »

Shortwave (SW) Transmitter with IC BEL1895

Here the SW transmitter circuit based on IC BEL1895. This particular transmitter circuit works in shortwave HF band (6 MHz to 15 MHz), and can be applied for shortrange communication and for educational purposes. The circuit is composed of a mic amplifier circuit, a variable frequency oscillator, and modulation amplifier stages. Transistor T1 (BF195) is… Read More »

1 – 9V Variable Desktop Power Supply

Here the variable desktop power supply which will convert a high input voltage (12V) from the SMPS / PSU of a desktop computer into small output voltage (1.25 to 9 volts). This converter will be very beneficial for electronics hobbyists. An adjustable three-pin voltage regulator chip LM317T (IC1) is applied right here to deliver the… Read More »

Simple Mobile Phone Battery Charger

The following diagram is a simple mobile phone battery charger circuit. The design is simple, easy to build and inexpensive. It use LM78xx regulator to make regulated and stable output voltage. Mobile phone chargers offered in the marketplace are quite expensive. The circuit shown right here shows up as a low-cost option to charge cell… Read More »

25 Metres Range, Short Wave AM Transmitter

Here the short wave AM Transmitter circuit design diagram. The circuit is quite simple and easy to build since it applies only a few electronic components. The primary feature of this transmitter is that it really is absolutely free from the LC (inductor, capacitor) tuned circuit and runs using a fixed frequency of 12 MHz… Read More »

USB Powered, Stereo Computer Speaker

This is the circuit diagram of USB powered stereo computer speaker, or it widely known as multimedia speakers for PCs. The circuit has single-chipbased design, low-voltage electrical power supply, compatibility with USB power from computer, simple heat-sinking, inexpensive, large flexibility and wide temperature tolerance. At the heart of the circuit is IC TDA2822M. This IC… Read More »

Shutter Guard

This is the shutter guard circuit which has sensitive vibration sensor, piezo-sensor. This circuit is specifically designed for outlets to defend towards theft. It can recognize any mechanical or acoustic vibration in its area when somebody attempts to break the shutter and instantly turn on a lamp and sound an alert alarm. A 15-minute time… Read More »

Electronic Horn

This is an easy, low cost and easy built circuit of an electronic horn which is designed close to quadruple op-amp IC LM3900 (IC1). IC LM3900 has four independent operational-amplifiers (A1 through A4) having a large output voltage swing. It is able to operate at up to 32V DC. The 1st op-amp (A1) is designed… Read More »