Adjustable Regulated Battery Charger

This battery charger circuit is regulated and adjustable to make this circuit able to charge the mosto NiCAD battery. This adjustable regulated battery charger circuit will work for single cell or multi battery cell which connected with series/parallel connection. The maximum voltage of the batteries should be 18V maximum. Power transistors Q1 and Q2 are… Read More »

Battery Charger + Small LED Lamp based Solar Cell / Photovoltaic

This is the circuit diagram of rechargable battery charger which use solar cell / photovoltaic as the DC source. This circuit works to charge 3 types of rechargable batteries that are lead acid, Ni-Cd and Li-ion. The lead-acid batteries are generally utilized in emergency lamps and UPS. The photovoltaic module or solar cell explained in… Read More »

Solidstate Automatic Power-Off on Mains Failing

The following schematic diagram is the circuit of  solidstate automatic power-off on mains failing. A really good number of circuits which shut down the power to the load on mains failure have definitely currently shown up in EFY. This circuit is different compared to other similar circuits since it consumes no electrical power when the… Read More »

Simple Mobile Phone Battery Charger

The following diagram is a simple mobile phone battery charger circuit. The design is simple, easy to build and inexpensive. It use LM78xx regulator to make regulated and stable output voltage. Mobile phone chargers offered in the marketplace are quite expensive. The circuit shown right here shows up as a low-cost option to charge cell… Read More »

Power Supply Failure Alarm

This is the ‘special’ circuit design of power supply failure alarm. The vast majority of the power supply failure alarm / indicator circuits require a independent power supply for themselves. However the alarm circuit introduced right here requires no extra supply power source. It utilizes an electrolytic capacitor to hold sufficient charge, to supply power… Read More »

Car Cigar Lighter to USB Power Socket

Here is the schematic design of car cigar lighter to USB power port. Nowadays, almost all computer systems have logic blocks for working with a USB port. In practice, a USB port is capable of supplying more than 100 mA of continuous electric current at 5V to the peripherals which are hooked up with the… Read More »