Modem UPS @ Rs250/-

 Submitted below a very low-cost UPS for the modem. Modems / WiFi routers are usually powered by an adaptor and while the utility power fails then internet connectivity is disrupted even if the power is interrupted for less than a second. Providing a commercial 500VA  UPS only for the purpose is an expensive proposition. Small duration power interruption is well taken care of with zero change over time as it uses no relays. The majority of apartments start the backup generator automatically within minutes while the modem power is interrupted. Even with an inverter or mains ups feeding the modem fail to avoid a reset of the modem as those UPSs use relay change over (for off kine UPS) resulting in power interruption for few milliseconds that the modem is not able to tolerate. Video here Materials required :-…

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Specifications of Our FM Transmitter Long-range stereo digital with warranty for 6 months

A very high quality stereo FM transmitter circuit , thoroughly time tested ,highly reliable, crystal controlled PLL based for zero  frequency drift is reviewed below. The main circuit uses a very popular IC -KT0803L ,to develop two channel stereo audio modulated FM signal from76 MHz to 108 MHz covering the FM band of  88 MHz to 107 MHz feeding  to 3 stage buffering before being fed to the final power amplifier using most commonly used 2SC1971 for 7 watt or MOSFET -RD15HVF1 for 15 watt. But unfortunately most commercially available 2SC1971 or  RD15HVF1 are duplicate. Thus if one ventures trying any circuit with this power Transistor/ MOFET usually are unsuccessful. So I strongly recommend to go for readymade units. Aux audio is directly fed at pin 6 & 7 while for mic input it is amplified by LM358 and then…

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