How to watch 2 TVs with remote by one set-top box

Use 2 TVs with single set top box . If the set top box has one HDMI and one set of AV available but no loop in loop out RF, then one can use the HDMI for the main TV while another TV at along distance of 30 to 50 meters can be connected from the AV output of the set top box.In case only one set AV is available but no HDMI then splitters can be used. Remote operation by an IR extender is also achieved while watching either or both TVs the same channel.No need to subscribe another set top box. Only restriction is that at a time both the TV or any one TV will be able view the same channel and not 2 different channels. Materials required Cat 5 cable of desired length. 15 meters at…

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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 https://youtu.be/kcugHjLLIPU Materials required :-…

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7 / 15 watt FM Transmitter PLL stereo digital circuit

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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Phase angle control using Arduino

Submitted below ac load management by delayed phase angle triggering to opto-coupler(U3)  interfaced triac (U4) for single phase load control using Arduino nano. Proteus file and the code for simulation are available at the bottom. For video watch at down below or use this link https://youtu.be/VpHoE_2MlEo Circuit Explanation It uses an Arduino nano which receives zero cross pulses (ZVS) at pin at Pin 2 and delayed output pulses are developed at pin 3. Control is done at A0 through a variable resistor (POT-RV1). A small step down transformer delivers 12 volt ac which is filtered by a bridge rectifier BR1 and then a blocking diode D1 and then filtered by capacitor C1 that feeds a 3 terminal regulator that gives 5 volt duly filtered again by C2 for powering the entire circuit. Function of D1 is very interesting. It separates…

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