Category Archives: Power Electronics



6V / 9V / 12V Battery Charger with Constant-Current Charging

This is the circuit diagram of battery charger which has many important features such as current-constant charging, overcharge protection, short-circuit protection, deep discharge protection and more. The constant-current charging is a popular method for lead-acid and Ni-Cd batteries. In this circuit, the battery is charged with a constant current that is generally one-tenth (1/10) of… Read More »

5V DC Regulated Power Supply with Short Circuit Protection

This is the circuit diagram of 5V DC regulated power supply which featured with short circuit protection system. There are 2 kind of output that are regulated 5V DC with short circuit protection and without circuit protection. The main circuit is protected from any damage due to short-circuit in the additional power supply circuit by… 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 »

Electronic Appliance Protector

This is a easy built and very low-cost circuit purposed to protect your electronic appliances / devices, such as Personal Computer, TV, recording devices, refrigerator, and other devices during sudden tripping and resumption of home mains supply. Appliances like refrigerators and air-conditioners are more inclined to damage due to such conditions.

Uninterruptible Power Supply with PIC17C43 Microcontroller

This is a MicroChip Uninterruptible Power Supply (UPS) reference design with PIC17C43 microcontroller. The document is available to download from the end of this post. At times, power from a wall socket is neither clean nor uninterruptible. Many abnormalities such as blackouts, brownouts, spikes, surges, and noise can occur. Under the best conditions, power interruptions… Read More »

Variable / Adjustable DC Power Supply 1.2V – 25V using LM338K

This is variable DC power supply circuit, or we can call it adjustable DC power supply which give us a 1.2V-25V output voltage. The power supply schematic above is taken from the datasheet of regulator LM338K manufactured National Semiconductor. The circuit uses IC LM338K as the voltage regulator, so we will get the stable and… 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 »