A blast from the Elektor archives: this 1998 battery tester uses a simple LED display to reveal a battery’s true condition under load — even below 1 V.

For those of us who don’t like to get their hands dirty, this simple soil moisture tester quickly checks the state of their plants and how much attention they need. Recommended for all plant owners!

Having good contacts is important – not only in your daily life, but also in electronics. In contrast to social contacts, the reliability of electrical contacts can be checked quickly and easily.