People often forget that many voltage regulator ICs have an upper limit (usually 35 V) on the input voltage they can handle. That applies primarily to types with a fixed output voltage. Adju... Read more
By configuring a comparator and a transistor to control the oscillator in a charge pump circuit, you enable the pump to generate a regulated output of — in principle — any desired value. Cha... Read more
This circuit belongs to the ‘car modding’ category. This is similar to the popular case modding in the computer world and has found its way into a substantial proportion of cars. The modific... Read more
A simple NiCd charger can be built using ‘junk box’ components and an inexpensive LM317 or 78xx voltage regulator. Using a current limiter composed of R3 and a transistor, it can charge as m... Read more
Inexpensive miniature transformers normally provide one or two secondary voltages, which is sufficient for generating a set of positive and negative supply voltages, such as are needed for o... Read more
a voltage supervisor chip to produce a clean reset pulse to the processor whenever a ‘brown-out’ condition of the power supply is detected. More complex designs employing multiple power supp... Read more
Ultrabright LEDs are becoming increasingly attractive for use in lighting and warning-signal applications. LEDs must be operated at a constant current to ensure that they continue to emit li... Read more
This circuit does the exact opposite of what most of this type of changeover switches attempt to do. Usually, a changeover switch is used with two PCs and one keyboard. This version, however... Read more
Ever wanted to build a positioning encoder? Here’s one and you do not even need any sensors. The circuit uses an LED as a light emitter and another LED as a light receiver. This is possible... Read more
In order to connect the open-collector output of a standard Conrad DCF receiver module (order number 121177), which has a relatively low operating voltage of 1.5–15 V and an NPN open-collect... Read more
