POWER LINE COMMUNICATION MODEM CIRCUIT

Here is a complete ASK modem dedicated to data transmission on power line
network, requiring very few external components. It could be also used on any two-wire
network for exchanging information by means of ASK carrier current technique (DC or
AC network). TDA5051A is used here as the main element for Power line communication modem.

The coupling network is the interface between the power line and the low voltage
TX_OUT and RX_IN pins of the modem. For low cost applications, when the insulation
with the mains is not required, a double LC network can be used, providing efficiency
without any adjustment or tunable components. When an insulation is mandatory, an
HF transformer should be used.

More detail about the circuit theory and PCB layout is given in the PDF attachment

Download PDF Here

Variable Power Supply with Digital Control

The most frequently used device in electronic workshops and laboratories is a universal power supply that
provides a variable, fluctuation-free out-put. Here we present a variable power supply with digital control that is simple and diodes to bypass undesired spikes and provide smooth and fluctuation-free power.

Download the PDF File from the link below

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Fire Alarm

The  smoke  alarm  circuit  presented here is based on the readily available  photon-coupled  interrupter
module  and  timer  IC  Ne555. The  photo interrupter module is used as the smoke detector,  while  timer  555  is  wired  in astable configuration as an AF oscillator for sounding alarm via a loudspeaker.

To download the PDF file for the circuit

Download PDF Here

Remote Control for Home Appliances

Connect this circuit to any of your home appliances (lamp, fan, radio, etc) to make the appliance turn on/off from a TV, VCD or DVD remote control. The circuit can be activated from up to 10 metres.


To download the PDF File which include the circuit

Download PDF Here

IR Remote Controller Timer

This infrared remote control timer can  be used to turn an appliance on/off  for a period of 0.11 second to 110.0 seconds. The circuit works up to 3 metres  without  using  any focusing  lens. This circuit costs  around Rs 100. This circuit is taken from EFY of May 2003

You can download the circuit with description from the link below


Download PDF Here