Best TP Link Archer Wireless Router Series

We pick 10 best TP-Link Archer Series . TP-Link Technologies Co., Ltd., is a Chinese manufacturer of computer networking products based in Shenzhen, Guangdong, China.

1.  TP-Link AC1750 Smart WiFi Router (Archer A7)

Dual Band Gigabit Wireless Internet Router for Home, it Works with Alexa, VPN Server, Parental Control, QoS

With parental controls and guest access.Keep your family safe and devices secure with advanced WPA/WPA2 wireless encryption.

Delivers Up to 2,500 sq.ft. exceptional WiFi coverage  throughout your home as three high-gain antennas and strong amplifiers connect every device—from the living room to the backyard. Check It Out

10 Best Professional Automotive Diagnostic Scanner 2021 By Brand

Whether you are a professional maintenance staff or not, it can provide professional technic support for your car. 

As a professional scan tool , it is able to deal with pretty much every auto repair scenario you can think of. 

Don’t worry, even a greenhand will feel it easy and convenient to use.

All Controlled Modules Scanning and Problem Diagnostics, such as Engine System, Airbags System, ABS System, 

Transmission System, Brake System, Alarm System, Keyless Entry System, TPMS System, Steering System, Wheel 

System, Fuel System, etc. It only takes a few minutes to finish full scanning of your vehicle and do a fast 

diagnosis and maintenance via reading/clearing codes, viewing freeze frame and graphing live data.

We picks 10 Best automotive scanner that compatible with almost all cars sold worldwide. 

10 Best Professional Automotive Diagnostic Scanner 2021 By Brand

White LED Lamp Circuit

Make  this  solid-state pocket torch using a few of these white LEDs. The simplest approach is naturally to use a separate series resistor for each LED, which has an operating voltage of round 3.5 V at 20 mA. Depending on the value of the supply voltage, quite a bit of power will be lost in the resistors. 

The converter shown here generates a voltage that is high enough to allow ten LEDs to be connected in series. In addition this converter supplies a constant current instead of a constant voltage. 

A resistor in series with the LEDs produces a voltage drop that depends on the current through the LEDs. This voltage is compared inside the IC to a 1.25 V reference value, and the current is held constant at 18.4 mA ( 1.25V devided by 68Ohm)

The IC used is one of a series of National Semiconductor 'simple switchers'. The value of the inductor is not critical; it can vary by plus or minus 50 percent. 220 uH coil at 3.5 A is good choice. Almost any type of Schottky diode can also be used, as long as it can handle at least 1 A at 50 V. The zener diodes are not actually necessary but they are added to protect the IC. If the LED chain is opened during experiments, the voltage can rise to a value that the IC will not appreciate.

Circuit

PCB Layout

Component Layout

Parts Lists

source ; Elektor 

Free Energy : Centrifugal dynamic power generating system using a lever structure Patent

This patent of Centrifugal dynamic power generating system using a lever structure invented by Daniel Paul Gorney. 

The free energy concept is the system/machine that operate perpetual motion indefinitely and independently without any other source of fuel, electricity, or any other renewable energy source other than gravity energy.

The free energy magnitude is over unity concept. the free energy result must bigger than energy for running the system/machine itself.

                                                                                                                                       

image courtesy google.com and Daniel Paul Gorney

DC Millivoltmeter with IC OP AMP 741

The Design of this DC Millivoltmeter presented here is a sensitive dc. electronic meter of several Megaohms input resistance and covering range from 5 Volt f.s.d to 5 mV f.s.d. 

This D.C. voltmeter designed to be used with 1 mA meter movement, this unit can be used as a pre-amplifier for a conventional test meter when switched to its 1 mA range for 5 V range. The range of meters from 5V f.s.d ,0.5V, 50mV, and 5mV f.s.d are provided, with input several Mega Ohm.