DIY Antennas, QRP, SDR & Ham Radio Projects from VU3DXR
Harnessing solar power to charge lithium-ion batteries is not only energy-efficient but also an eco-conscious choice for portable electronics. In this article, we explore a compact and reliable lithium-ion solar charger circuit that uses a few standard ICs: LM2941, LM3420-8.4, and LMC662. Designed for charging a 2-cell Li-ion battery pack, this setup is ideal for […]
This is a clever Battery low power indicator circuit designed by G3AGX that provides a visual indication when equipment is drawing power, even at very low current levels. The circuit is particularly useful for monitoring standby power consumption or confirming that equipment is actually powered on. Battery Low Power Indicator Circuit Analysis The heart of […]
Simple zener diode tester Ever found yourself with a handful of zener diodes, wondering if they’re still good or what their actual breakdown voltage is? Zener diodes are incredibly useful components for voltage regulation, but sometimes, their markings can be ambiguous, or you just need to quickly verify their functionality. That’s where a simple zener […]
This white led torch circuit provides an effective solution for powering white LEDs. It is ideal for flashlights, emergency lighting, and various other applications. The circuit operates efficiently from one or two primary cell batteries. The core of the circuit involves a transistor (Q1) and a tapped inductor, forming a blocking oscillator. When the power […]