EXPERIENCE WITH BUCK REGULATOR

We want to see the characteristics of buck regulator given in datasheet of SG3524. This is our first experience of BUCK Regulator (5V) without using the transformer and is working very nice.

Instead of TIP115 PNP transistors easily available BC557 and BEL369 are used to form the Darlington pair. The Input current drawn is 100mA@20V with the output of 300mA@5V. The circuit is working at 10 KHz frequency and the inductance is 1.2mH. The Core and bobbin are purchased from the JINANICA.TO increase the efficiency of the circuit schottky diode is used.

The circuit Diagram is taken from the SG3524 datasheet: click here fig 3:

The pictures of buck regulator is given below:

LAKE CITY SPECIAL

Greetings to all,

Lake city special RX (7085KHz) comes with few modifications in the GR40 RX. VXO works @12MHz, BFO and IF filters works @ 4.915MHz. i.e (12MHZ-4.915MHz=7.085MHz).
The block diagram and schematic are given:

Bootloading/Burning hex file to Atmega328 using Parallel port

Dear all,

While working using arduino, Bootloader has crashed, we came with the solution for bootloading/burning hex file into Atmega328 without arduino using icsp pins in microcontroller and parallel port. we have taken the circuit and explanation from avrprogrammers.com.

Here is a solution for Bootloading/programming Atmel atmega328 uisng ICSP pins.

Connect the atmega328 pins(MOSI, MISO, SCK, RESET and GND) as shown in schematic, power up the circuit with five volts. To do this I have used the ISP Programmer 1.2.0.56.
For software click here.

Here is the procedure for using this software:-

VXO

Dear all,

We wanted to make a simple solution for Lake City Net operating at 7085KHz daily between 8:15Am and 8:30Am. We have chosen IF as 4915KHz for which standard low cost crystals are available. This requires a LO of RF+IF=12MHz, We have happily configured a 12MHz VXO. This VXO fortunately covers 11995KHz also giving rise to coverage of CHARMINAR NET operated at 7080KHz daily until 8Am. Below is picture of experimental VXO and the table contains test result.

Different values of the crystal with different capacitor in X position

BATTERY BOOSTER TESTING

Dear all,

Test setup of Battery booster is in the below figure:

This battery Booster is designed for 20A and claims for 10A. We tested it upto 5A.

ALCOHOL SENSOR USING PIC16F887

Dear all,

As a College project we  made an Alcohol sensing micro controller using PIC16f887and MQ3 sensor. When it sense the alcohol the buzzer will turn ON.