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Above circuits are based on TEA2025 is a monolithic integrated audio amplifier in a 16-pin plastic dual in line package manufactured by UTC .Circuit has an Internal Thermal Protector. It is designed for portable cassette players and radios.
Portable Audio Amplifiers - [Link]
Th1, the 50K thermistor, is a standard type. Mine was a bar or rectangular looking thingy. Available from Tandy/Radio-Shack. Almost any type will do. I experimented with different models from 22K to 100K
and all worked fine after replacing the trimmer pot. The one used in the above circuit diagram was a 50K model. This 50K was measured at exactly 25 °C and with 10% tolerance.
Automatic Fan Controller - [Link]
Here is a white-LED-based emergency light that offers the following advantages:
1. It is highly bright due to the use of white LEDs.
2. The light turns on automatically when mains supply fails, and turns off when mains power resumes.
3. It has its own battery charger. When the battery is fully charged, charging stops automatically.
Low cost / Automatic Emergency Light – [Link]
This FM transmitter (FM Tx) is about the simplest and most basic FM Tx it is possible to build and have a useful
transmitting range. It is surprisingly powerful despite its small component count and 3V operating voltage. It will
easily penetrate over three floors of an apartment building and go over 300 meters in the open air. The circuit
we use is based on a proven Australian design.
Simple FM Transmitter – [Link]
The circuit is based around {LM4702}manufactured by NATIONAL semiconductors&{MJ11029-MJ11028} by ON semiconductors It is a high fidelity audio power amplifier. Designed for demanding consumer and pro-audio applications.
600W Audio Amplifier – [Link]
This circuit is an ETHERNET controller I use the PIC18F452 and the mikroC C Compiler. I use also the JAVA SCRIPT information you can get from www.w3school.com I Control 8 outputs throw the WEB and transfer time information also.
Ethernet Controller – [Link]
This is an early picture of my discolight effect. Because of the AGC circuit theres no need for potentiometers for sensitivity adjust. I replaced them with trimmers. Now the microphone is on the control electronics because theres no need to place it outside the box and the possible noises from the surroundings are reduced.
PIC16F84A discolight effect with bass beat control – [Link]
Yes folks, it’s time for another horse to bolt from the Downunder stable of telephone intercoms (unfortunately before the gate could be shut on it…) and other zany electronics type ideas. The circuit you are about to see is the culmination of some effort at improving the basic Link intercom design. You may think that pulse dialing is ‘old hat’ nowadays, but the exercise of building and testing the Link ‘P’ in this format, and understanding how it all works, is well worth the effort. Not to mention all those out there who have the old style rotary dial phones as collectables – you can now make them work for you, or display them actually working with confidence.
The Link “P” – Privacy Link! (Telephone Intercom) - [Link]
This multimeter was designed to measure output voltage and current in a PSU, where the current sense shunt resistor is connected in series with load at the negative voltage rail. It needs only one supply voltage that can be acquired from main PSU. An additional function of the multimeter is that it can control (switch on and off) an electric fan used to cool the main heatsink. The power threshold at which the fan switches on can be adjusted using One Touch Button Setup.
Voltmeter + Ammeter LCD panel - [Link]
Since iButton DS1990A introduced in market from Dallas Semiconductor (MAXIM), it has been used in many applications concerning security, access control systems etc. In this project we will use iButton as a key to an electronic lock. This electronic lock can use many different kinds of iButtons and can store up to 9 different keys. One of the keys is the master key and is permanent stored in memory. With the use of master key we can add or remove slave keys.
iButton electronic lock – [Link]
