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Power Supply Circuits
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Battery Charger Circuits
3.6 Volt cell phone battery meter circuit
This is a similar circuit to the above and provides a 4 LED bar graph indicating the voltage of a common 3.6 volt Lithium - Ion recharable cell phone battery. The reference voltage is provided by a TL431 programmable voltage source which is set to 3.9 volts where the TL431 connects to the 1K resistor. The lower reference for the LED at pin 14 is...
2 Cell Lithium Ion Charger circuit
This circuit was build to charge a couple series Lithium cells (3.6 volts each, 1 Amp Hour capacity) installed in a portable transistor radio..
Constant Current Battery Charger circuit
A simple method of charging a battery from a higher voltage battery is shown in the circuit below to the left. Only one resistor is needed to set the desired charging current and is calculated by dividing the difference in battery voltages by the charge current..
Versatile Micropower Battery Protector circuit
Protect your expensive batteries from discharge damage with this mini-sized electronic cutout switch. It uses virtually no power and can be built to suit a wide range of battery voltages..
In-Car Charger And Switcher Circuit For SLA Battery circuit
The SLA battery is charged from the vehicle s battery. When the engine is running, the voltage remains fairly constant, which greatly simplifies the charging circuit. If the SLA battery is fully charged, any further charging current from the vehicle battery is limited by a 3.3W 5W resistor (R1). If the SLA battery is deeply discharged, the...
NiMh and NiCd Battery Charger Circuit
This automatic NiCd charger for 9V NiCd batteries is using 555 timer properties and is very easy to build. Why is an automatic 9 volts NiCd battery charger? Because you can leave the battery for charging as much as you like: it will be always completely charged and ready for use when is needed. It wont be overcharged and it will not discharge....
Solar Panel Based Charger And Small LED Lamp circuit
You can save on your electricity bills by switching to alternative sources of power. The photovoltaic module or solar panel described here is capable of delivering a power of 5 watts. At full sunlight, the solar panel outputs 16.5V. It can deliver a current of 300-350 mA. Using it you can charge three types of batteries: lead acid, Ni-Cd and...
24V Battery Charger Schematic
240/24Vac(rms) transformer was used. After rectification and filtration i got about 30Vdc. Therefore the transformer and diode rating should be well chosen to meet your demand At the current limiting stage, transistor U1, Q1 and resistor R1 plays the vital roll in the current limiting; When U1 switches on it short circuits the gatevoltage of Q1...
iPod charger Schematic
First off I should mention that this is supplemental Instructable to the countless others that show you how to build a USB charger. I am assuming you..
You will need this project when you have an extra mobile battery or you need to charge any lithium, Lithium ion or Lithium Polymer battery. Maximum c..
Joule Thief Charger
Let your dead battery give life to another! An open circuit Joule Thief can put out 50 or more volts. Enough to charge a AA or AAA Nicad or NiMH rec..
Reverse Engineering an Electric Fence Charger
This product includes some logic circuitry used to control the timing of the output pulses, which will be discussed in a later step. The logic circui..
The Super Capacitor Flashlight with Custom Charger and Voltage Booster
Before I begin talking about the schematic, let it be known that there are four hardware blocks to this circuit: 1) The wall transformer 2) The charge..
Wireless Power Charger Schematic
To build it, just follow the schematic as shown. (If you need help, please, do not hesitate to message me!) If you`re having trouble identifying the..
ISL88731 SMBus Level 2 Battery Charger
The ISL88731 is a highly integrated Lithium-ion battery charger controller, programmable over the SMBus system management bus (SMBus). The ISL88731 is intended to be used in a smart battery charger (SBC) within a smart battery system (SBS) that throttles the charge power such that the current from the AC-adapter is automatically limited. High effi
ISL6291 Li-ion/Li Polymer Linear Battery Charger
The ISL6291 provides a low-cost integrated charger solution for single-cell Li-ion and Li Polymer rechargeable batteries. No external pass element, current sensing resistor, or reverse blocking diode is required with this solution. The ISL6291 is a constant-current (CC)/constant-voltage (CV) charger. The constant charge current is programmable up
Solar Panel Optimizing Battery Charger
Figure shows the V-I curve for a typical solar panel (Sharp ND-224U1F), and output power under different lighting conditions. The solar panel behaves like a constant current source at high current, and like a voltage source at low current. The transition region is where the highest power can be obtained. The voltage and particularly the current...
Battery Charger Regulator
Most off-the-shelf car battery chargers cannot not be left connected to the battery for long periods of time as over-charging and consequent battery damage will occur. This add-on circuit is placed in series with the battery being charged and is powered by the battery itself. In effect, the circuit uses a high-current Mosfet to control the chargin
Float Charger For NiMH Cells
Although not a new device, the LM317 is still a high-performance regulator. Its output voltage is essentially immune to fluctuations in load, supply voltage and temperature and this makes it ideal as the central element in a float charger for NiMH cells. Float charging has the advantage of keeping the cells fully charged and ready to use without t
IC Controlled Emergency Light With Charger Circuit
Here is the circuit diagram of IC Controlled Emergancy Light With Charger or simply 12V to 220V AC inverter circuit. The circuit shown here is that of the IC controlled emergency light. Its main features are: automatic switching-on of the light on mains failure and battery charger with over-charge protection. When mains is absent, relay RL2 is in
Lead Acid Battery Charger 1
Except for use as a normal Battery Charger, this circuit is perfect to `constant-charge` a 12-Volt Lead-Acid Battery, like the one in your flight box, and keep it in optimum charged condition. This circuit is not recommended for GEL-TYPE batteries since it draws to much current. The above circuit is a precision voltage source, and contains a tempe
Lithium-Polymer Peak Charger
This circuit was developed to charge the Lithium-Polymer cells used in a model aircraft. Lithium-Polymer cells are incredibly lightweight compared to Ni-cad battery packs of the same voltage and amp-hour rating. Their only drawback is that they require a rigid charge and discharge regime to achieve maximum life. The most important points of note a
Low-Power Car/Bike USB Charger
We tested a regular charger and found that it consumed 13mA with no load. Like many others, it has an integrated power LED and that would contribute significantly to the standby current consumption. However, since the cigarette lighter socket is only powered when the engine is running, there is no real reason for the designers of these car supplie
Nicad Charger Uses Voltage Cut-Out
This circuit charges two NiCad cells with a constant current and features dual charging rates, voltage cutoff and an audible alarm. The circuit is powered by a 12VAC centre-tapped mains transformer, together with two rectifier diodes (D1 & D2) and a 1000mF filter capacitor. A 7806 3-terminal regulator is used to generate a 6V rail for the remainde
NiMH Charger For Up To Six Cells
It is impossible to imagine present day society without any batteries. Count the number of gadgets in your house that are powered from batteries, you will be stunned by the number of batteries you will find. The majority of these devices use penlight batteries and if you`re a little environmentally conscious you will be using rechargeable batterie
Solar Panel Based Charger And Small LED Lamp
You can save on your electricity bills by switching to alternative sources of power. The photovoltaic module or solar panel described here is capable of delivering a power of 5 watts. At full sunlight, the solar panel outputs 16. 5V. It can deliver a current of 300-350 mA. Using it you can charge three types of batteries: lead acid, Ni-Cd and Li-io
Solar-Powered High Efficiency Battery Charger
This is a simple NiCd battery charger powered by solar cells. A solar cell panel or an array of solar cells can charge a battery at more than 80 % efficiency provided the available voltage exceeds the fully charged` battery voltage by the drop across one diode, which is simply inserted between the solar cell array and the battery. Adding a step-do
Switchless NiCd-NiMH Battery Charger
This circuit may be used to replace the single current limiting resistor often found in dirt cheap battery chargers. The alternative shown here will eventually pay off because you no longer have to throw away your NiCds after three months or so of maltreatment in the original charger. The circuit diagram shows an LM317 in constant-current configur
Linear SuperCap Charger with Current-Limited Ideal Diode and V/I Monitor
The LTC4425 is a constant-current/constant-voltage linear charger designed to charge a 2-cell supercap stack from either a Li-Ion/Polymer battery, a USB port, or a 2. 7V to 5. 5V current-limited supply. The part operates as an ideal diode with an extremely low 50m © on-resistance making it suitable for high peak-power/low average power...
Alkaline Battery Charger Schematic
The lower charge rate, the better the charge and the less chance of a cell leaking electrolyte. Also, if a cell becomes too flat or completely flat, it will not take a good charge and will also probably leak electrolyte and possibly even pop open. The idea here is to keep them topped up. Lets say you have fresh batteries in a torch and you used...
Portable phone charger
The phone is a Siemens S65. The official charger that came with the phone says 5V at 420mA. Because these things do not always actually deliver what is printed on them I measured the voltage myself. This is actually quite hard with the tiny contacts on the connector, especially when it also has to be plugged into the phone. Without a phone...
USB phone charger
A portable phone charger for a Siemens mobile phone. Since I don`t use that phone anymore and recent phones can usually be charged with a USB connector I built a new version of the charger. This time with a proper PCB, a USB connector and a higher current capability. Just as the previous charger it is basically just a step-up conve
Free Energy Circuits
AC-DC & DC-DC Circuits
Solar Cell Circuits
Current Limiting Circuits
Micro Power Circuits
High Voltage Circuits
Switching Power Supply Circuits
Ultrasonic distance finder circuit
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is measured. There are three main categories of distance measurement methods in use: a) By...
Simple Metal detector circuit with CD4030
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to find something potentially valuable, hidden a few centimeters below the soil. So many...
Fully automatic watering circuit for flower pots
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This circuit comes as a solution to this problem. Depending on humidity of the pot at...
Simple deep searching metal detector circuit
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the circuit of this metal detector, it is possible to detect a metal coin in depth of 90 to...
Sub-Harmonic Bass Converter for Electric Guitars
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound, such as filtering or distortion. Instead, a frequency division system produces outputs...
Echo Depth Sounding Sonar for Boats
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the calibration of the rope. This arrangement still exists in some yachts. The big...
100W HiFi Audio Amplifier Circuit
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power supply must be symmetrical so that no electrolytic capacitors are needed at the outlet....
Plant-Pot Water Level Indicator Circuit
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower. The circuit of the device is shown in Figure 2. The water detection is made from the bottom...
Analogue Sound Preasure dB-Meter Circuit
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to have a good accuracy we will get the limits of 20Hz to 20KHz. A sound to be heard does...
Digital Signal Integrity
Interconnection and Timing of Digital Circuits
CMOS Circuits Tutorial