How to repair an analog oscilloscope using a multimeter only

Today analog oscilloscopes have been completely replaced by digital ones, however the fascination of such vintage stuff cannot be explained to those who have never used one. This is not a debate about which one is better: nowadays all kind of measurements are performed using DSO and is very difficult to find out an old glorious analog scope. If you have it and if it isn’t working, before throwing it away think that you have in your hands an old electronic device made by BJT, JFET, diodes, discrete components and a few logic gates, flip flop and multivibrators, that kind of stuff that you can fix by yourself. Continue reading

DIY milliohmmeter

DIY MILLIOHMMETERThis is an example of a simple and cheap milliohmmeter that can be made by every maker. The core of the circuit are a current source (LT3092) and a current sense (INA225): a costant current flows through the milliohm resistor under test and the voltage at the current sense output gives the value of the resistor (V=R*I). Continue reading

Smart charger and 5V portable power supply

 

SMART CHARGERNowadays almost every electronic gadgets are powered or recharged by a USB port (full size, mini o micro) as well as many of consumer products we use every day, including our smartphone. To recharge or give power to such products, there are many portable rechargers which have a rechargeable lithium battery and the electronics necessary to convert the battery voltage to 5V and to recharge the internal cell. The cost of these smart chargers is very affordable but we’re hardware makers, aren’t we? So why don’t to do it by ourselves to give power to our Raspberry Pi, arduino or Beaglebone black? We’ll show you a possible way to design one of these intelligent portable power supply. Continue reading