In this video I’m showing how I’ve built a very simple battery backup circuit for my home alarm system. The circuit charges a 12v lead acid battery and in an event of a power loss, it transfers the ...

As the number of Power Over Ethernet (PoE) powered device (PD) applications grows, market pressures are driving designers to lower the cost and complexity of the DC-DC converters that power them, ...

The improved one-BJT current-limiting supply is not much different than the primitive circuit, though its one additional resistor does change the circuit behavior. The improved circuit is shown below.