This is a TL431 comparator fuse that can be made on a breadboard,pcb or even copper tape. It uses a 1.5V Battery(Can be AA,AAA,C or D). Its used to add 1.5V to the voltage drop across the current sense resistor. This is needed since it can only turn on at 2.5V at the reference pin. …
Tag Archives: test equimpent
Resistor RJ45 Tester
This is a simple network cord tester that uses just 8 unique resistors. The values/wattage doesn’t matter as long as the meter can read them. They should be in the kiloohm range. I have made an Excel spreadsheet file that you can enter all 8 of the resistors and get the total parallel resistance. The …
Basketball pump signal injector
This is a simple signal injector that can fit inside a mini basketball pump it requires: This signal injector can come in handy for repairing radios, amplifers and old TVs and also square wave generator in a probe. Later on I will make a version that uses C1 and C2 as 470nF and R3 and …
DIY cable tester
In this blog I will show you two ways to make a cable tester. The 1st way uses a arduino (software controlled). The 2nd way uses a decade counter chip(CD4017) and a flashing LED. I am going to order the Dual RJ45 jack to screw terminals from eBay. The other connectors are from parts-express. I …
De Sauty’s Bridge
This bridge is good for measuring Capacitors. What you do is hookup high impedance headphones to the output(V2 in the NL5 Circuit). Then adjust the resistor(s) , you can use the calculator below to find a suitable resistance for the resistors. This works like a Wheatstone bridge except one side has capacitors. The calculator calculates …
$32 dollar isolation transformer
Here’s a simple easy to build Isolation Transformer that you can buy from All Electronics. Here’s what you need: 1x 120VAC Output transformer 1x outlet connector 1x power cord You can add a 1/2A fuse that goes on the output of the transformer
Circuit Simulator