A popular category of aiming/pointing aids is the reflex, or “red-dot,” sight. This system finds use in such diverse applications as astronomy, archery, and shooting. In the reflex sight, light from an internal source typically a ...
You sometimes need to drive a white LED from one 1.5 V battery. Unfortunately, the forward voltage of a white LED is 3 to 4 V. So, you would need a dc/dc converter to drive the LED from one battery. Using the simple circuit in Figure 1, you can ...
This Design Idea describes a single white-LED torch, which can be housed in an empty glue-stick tube and has a long rechargeable-battery life. The circuit is constructed with just a few commonly available parts. This torch has proven to be highly ...
TA Babu EDN LED technology is opening the door to a variety of high-power-illumination applications. The circuit in Figure 1 can let you know when ac power is available. To drive a power LED from the ac line requires a converter or a similar ...
Robert Most EDN Circuits that latch one-of-N switches usually use a digital approach. Such circuits are often useful in human-interface situations, such as audio-mixing consoles, video-feed selection, or current-loop-control redundancy systems. In ...
The circuit in Figure 1 is a good choice if you need a power supply with high efficiency and you don't want to use expensive dc/dc-converter ICs. The heart of the circuit is IC 1 , the common, inexpensive LM7805 linear regulator. The external ...
A microcontroller requires dc operating power in the 2 to 5.5 V range, an amount that a battery or a secondary power source can easily supply. However, in certain situations, a microcontroller-based product must operate directly from a 120 or 220 ...
Art Hogrefe EDN A number of circuits, such as level detectors and AM demodulators, benefit from a rectifier with a low offset voltage. Silicon diodes have an offset of approximately 0.6 V and do not work well in low-level circuitry. A Schottky ...
Richard Dunipace EDN Low-cost DVM (digital-voltmeter) modules are economical and can significantly reduce design time for instrumentation. Yet, these modules also involve a significant number of design challenges. For example, their inputs are not ...
Carl Pugh EDN Most circuits use bypass capacitors and can deliver substandard performance if the capacitors have poor pulse characteristics. Few if any articles cover how to test bypass capacitors for pulse characteristics. The circuit in Figure 1 ...