Circuit Lake » Analog

Infinity Bug Device

admin — Sat, 03 Dec 2011 02:08:14 +0000

The infinity bug is connected across the phone-line of a distant phone in parallel mode. It uses surface-mount resistors, capacitors, transistors and diodes. It gets operating current from the phone line (leech device), no external power supply is required.To use the Bug, the distant phone is rung. After having a conversation with the person [...]

5W VHF TV Transmitter

admin — Thu, 06 Oct 2011 05:13:27 +0000

This VHF TV TRANSMITTER can be used to transmit movies from your PC to your living room, run a college TV station, hotel cable system info pages, re-transmit the TV program you’ve never been able to receive in your valley, cover rural areas of Africa with TV signal from satellite stations and other system [...]

Telephone FM Transmitter

admin — Thu, 28 Jul 2011 21:07:29 +0000

This project can transmits phone conversation up to 30 metres (100 feet) to an ordinary FM receiver. You can experiment to get greater transmission range away from the phone line by adding an aerial (about 150 cm of 26 gauge wire) to the collector of T2 (see circuit below).To use phone transmitter, you need to [...]

Inductivity Meter Using IC 555

admin — Fri, 01 Jul 2011 22:11:33 +0000

The projects shows you how to build simple low cost Inductance Meter based on popular IC 555. The 555 works in its most simple rectangle oscillation configuration. In this mode, the duty-cycle should be around 50%, but this depends on the load on pin 3. Over the amplifying transistor Q1 the AC is given on [...]

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Simple Solar and Wind Charge Controller, IC 555

admin — Thu, 30 Jun 2011 05:11:03 +0000

The purpose of the project is to build a simple charge controller for solar and wind systems based on IC NE555 Timer. Michael Davis, the designer, decides to use IC 555 instead of MCU because he worried that the microcontrollers would be too expensive or difficult to obtain in some parts of the world, and [...]

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Crystal Radio With External Speaker

admin — Thu, 07 Apr 2011 00:37:10 +0000

Crystal radio is the simplest type of radio receiver, and can be handmade with a few inexpensive parts, like an antenna wire, tuning coil of copper wire, crystal detector and earphones. It needs no battery or power source and runs on the power received from radio waves by a long wire antenna.However if you hard [...]

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Capacitor ESR Tester

admin — Sun, 06 Mar 2011 19:45:24 +0000

ESR (equivalent series resistance) is one of the characteristics that define the performance of an electrolytic capacitor. Low ESR is highly desirable in a capacitor as any ripple current through the capacitor causes the capacitor to heat up due to the resistive loses. Typical capacitor checker measures the capacity of the test capacitor. Some advanced [...]