Circuit Splash

This Power density calculator allows you to measure the power density from an antenna at a certain distance by providing the output power and gain values.

LM386 is a low voltage audio amplifier and frequently used in battery powered music devices like radios, guitars, toys etc. The gain range is 20 to 200, gain is internally set to 20 (without using external component) but can be increased to 200 by using resistor and capacitor between PIN 1 and 8, or just with a capacitor.

Bust out that 555 timer and use it to build your own AM radio transmitter. The circuit that is using only needs the timer chip, an NPN transistor, three caps, three resistors, and a potentiometer. It generates an amplitude modulation signal around the 600 kHz range which you will be able to pick up with any normal AM radio.

In this project we are going to design a 25V range digital voltmeter by using ATMEGA32A microcontroller. In ATMEGA, we are going to use 10bit ADC (Analog to Digital Converter) to build a digital voltmeter. Now the ADC in ATMEGA can not take a input more than +5V, so for getting a higher range we are going to use a voltage divider circuit.

This is an interesting project in which we explore the power of an Arduino and Android to create a Surveillance device which uses Arduino and Ultra Sonic Sensor to broadcast the information to a mobile application (Android) using Bluetooth.

This battery life calculator allows you to estimate the battery runtime. You can calculate how long the battery will last depending on the battery capacity and the amount of current consumed by the circuit.

But IR remote has some limitations like low range and it only works in Line of Sight etc. So these limitations can be overcome by converting the IR signal into RF signal. RF signal does not required line of sight and have much better and long range then IR remote.

You must have seen automatic door openers in shopping malls and other commercial buildings. They open the door when someone comes near the entrance and close it after sometime. A number of technologies are available to make such kinds of systems like PIR sensors, Radar sensors, Laser sensors, Infrared sensors, etc.

The basic circuit operates at a frequency determined by R1, R2 and C1 and has a pulse width range of 0 to 100 percent.

The following diagram shows a basic circuit with an open collector output that would require a pull up resistor at its output. The parts values are the nominal values of the components used.