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Power Supply Circuits
Battery Charger Circuits
Battery Charger Circuits
Quick NiCd - NiMH Charger
The charger is build around a LM317 (click to download datasheet) adjustable regulator. The charge starts when a battery is connected between pins JP1-JP4 or JP2-JP4 or JP3-JP4. For example, if a battery is connected to JP1-JP4 pins then the current that flows cause a voltage drop to R1, then D1 causes a voltage drop of 0,7 volts and ?1...
Battery charger and PSU
This circuit was created for digital cameras. It's known the digital cameras have considerable power consumption. For example my camera Minolta E223 requires approximately 800 mA. In practice a mains power supply or high capacity NiMH accumulators (batteries) can satisfy this demand. This circuit consists of two parts, charger and adapter. The...
3.6 Volt Lithium Ion Battery Charger (PIC12F675)
Lithium Ion batteries pack a lot of power by weight compared to other types. There are 2 things that need to be handled differently than nicad on NiMH. They cannot be used as a direct substitute (even if they look like other AA's) since they run at about 3.6 (or so) volts. They cannot be charged in the same way as nicad or NiMH.
This device is built around a PIC12F675 (a dandy little part from Microchip). The number of cells (1 to 8) is programmed in using the one button. The cell count is saved in EEPROM the next time you power up the device. Using just one button for all operations is a bit tricky, but easy once you try it a few times. There are 2 types of button...
FAST CHARGER controlled by a 68HC11
Note first the battery to be treated at the center of the figure. It is connected to contacts of a relay. The diagram shows the relay at rest. Under these conditions the battery is in SHOCK . His pole - is grounded and its positive pole to the circuit of constant current discharge. This circuit consists of N-channel MOSFET controlled by the TM2...
PIC16F84 Solar Charger
The previous version of this device used pulse width modulation (pwm) to control the power from the five solar panels to charge the battery bank. Under full sun conditions the MOSFETS got a bit warm and the whole unit radiated a lot of RFI. This design uses a set of relays - one for each panel. If the controller decides the battery voltage is...
Solar Charger circuit
Few years back, I had been working on a project for solar auto lighting. The light will turn on when the the solar panel voltage drop below a set point indicating that it is dark. The detection is done by using D2 in the schematic. The zener diode value will be adjusted so that the transition between the switch depends on the amount of light the...
Lead Acid Battery Discharge protector
In perfect discharge the batteries of lead acid, exists the fear they are destroyed. This circuit makes the work, this detection of discharge, protecting the batteries from destruction. At the discharge the polar voltage of batteries 12V of Lead acid, is not allowed it is decreased under 10.8V, thus we have warning with the turn on of Led, when...
Ideal Car Battery Charger
The usual chargers of battery automotive, are simple and cheap appliances that charge continuously the battery, with a rythm of few amperes, for the time where the appliance is ON. If the holder do not close in time the charger, the battery will overcharge and her electrolytic faculty are lost with evaporation or likely exists destruction of her...
Stand-by Battery Charger
This simple circuit will find many applications as a battery eliminator for low power requirements. It consists of a transformer, a bridge rectifier and an electrolytic capacitor followed by a zener controlled series pass transistor. The output is stabilized at +7.5V. The stand-by battery, 7.5V, in series with D7, floats across the output...
Lead-Acid Battery Charger
The circuit is actually a half-wave rectifier. It only charges the battery on every half cycle. The plug pack doesn't like this as it leaves residual flux in the core of the transformer and causes it to overheat. But that's the only drawback with the circuit. The SCR turns on during each half cycle and current flows into the battery. A...
Nickel Metal Hydride ( NiMH ) Charger
This circuit will charge a 12v battery (10 NiMH cells) @ approx 220mA. It is a very simple circuit but requires correct setting up. The circuit is designed around a 12vDC, 500mA plug pack. This type of plug pack delivers about 17.5v to 18.5v DC on no-load and about 13v when the current is 500mA. Our circuit delivers 220mA to a set of AA...
Charger for 12V lead acid battery
A battery is a vital element of any battery-backed system. In many cases the battery is more expensive than the system it is backing up. Hence we need to adopt all practical measures to conserve battery life. As per manufacturer's data sheets, a 12V rechargeable lead-acid battery should be operated within 10. IV and 13.8V. When the battery...
The Simplest Car Battery Charger
This very simple circuit uses a transformer ,two diodes , a capacitor and an ammeter. To charge a battery just connect the + and - terminals of the circuit to the corresponding terminals of the battery. When the battery is not charged, the ammeter reading shows 1-3 amps. When the battery is fully charged the ammeter reads Zero or nearly...
Charge Limiter circuit
Here is a deluxe version of the simple charge rate limiter, using the same idea but with the ability to charge two packs simultaneously from a single wall charger. For circuit description and parts list, see the simple charger page. Since wall chargers provide about 55 mA, you should not use this dual circuit to charge batteries at rates greater...
12V battery charger with 555
The charger consists of two stages: The first is a capacitive voltage doubler, which uses a 555 timer IC driving a pair of transistors connected as emitter followers, which in turn drive the voltage doubler proper. The doubler has power resistors built in, which limit the charging current. The second stage is a voltage regulator, using a 7815...
Reasonable Car Battery Charger
This charger will charge any 12V lead acid battery including flooded, gel and AGM. It is fully automatic and will charge at a rate up to about 4A until the battery voltage reaches a preset point at which it will switch to a very low current float charge. If the battery voltage drops again the charger will begin charging until the voltage once...
NiCd/NiMH Battery Charger
Here we use the PIC16711. Rechargeable battery capacity is rated in mAH (milliampere-hours). The total capacity of a battery is defined as "C", that is it can supply C mA for 1 hour, or 2C for 30 minutes etc. Charge rates can vary from trickle charges to keep the battery 'topped up' of 3.3% of C to 5% of C, a slow current charge of 10% of C to...
Capacitor Charger Lead Acid Battery
Leaving aside the complex chargers, "stuffed" electronics capacitor charger is one of the best connections. Charging current is limited by the resistor (or other element of the changing excess energy into heat), but the reactance of the capacitor to the primary side. The charger is not heated, the greatest loss occurs only at the transformer and...
Built-in battery charger, Li-Ion
Build-in charger for instruments powered by single lithium-ion or Li-Pol accumulator. If external power supply not conected to charger, current back from the accu charger is very small. New version improved temperature stability and Not Needed NTC thermistor. After a simple adjustment can be from initial engagement to launch a thermistor to...
Single Cell Lithium-ion battery charger
The rechargeable Li-ion, I began to intensely interested last summer, when I managed to bring a holiday without a phone charger. After several experiments involving originated in Figure 1, which has proved. Involvement of the stage provides a limited current charging and constant voltage. Charging current from the rectified voltage of the...
NiCad charger with independent discharge
If you use different batteries with actual capacity, with different self-discharge rate of batteries from different manufacturers, you will perhaps throw further described charger. Because each cell can be discharged separately recharge, can be charged with varying articles carrying charge. All of the described nabíjely NiCad battery chargers,...
9 V NiCd or NiMH accumulator charger
Most universal chargers to charge the battery 9 V (8.4 V more). However, while the charging of NiCd or NiMH rechargeable governed by a special circuit or a microprocessor, 9 V batteries are recharged mostly from current sources. I use several of these batteries in measuring instruments, and several have already happened to me, that I forgot the...
Multiple Capacitor Charger
The circuit is shown in Figs. 1-2 and tested succesfully. This is a 555 timer IC based charger. The circuit is operated by 8.4VDC. For R1=2.7K, R2=3.3K, and C1=10nF, oscillation frequency is about 25KHz. Measured period is about 40µs when there is no toroid load. In the presence of toroid, period shrinks to about 30µs. So the frequency jumps...
1n5818 Solar Charger Controller
12V Battery Charger for Lead/Acid
The battery charger circuit below is very simple to build requiring only a handful of cheap parts and an extra winding on your power tranny (or a separate tranny). Since the charger described is not active during sound reproduction, I have made no criteria on parts quality, so el-cheapo was the way to go. There are many circuits available for char
Automatic 12V Lead Acid Battery Charger
R2 will have to be adjusted to set the proper finish charge voltage. Flooded and gel batteries are generally charged to 13. 8V. If you are cycling the battery (AGM or gel) then 14. 5V to 14. 9V is generally recommended by battery manufacturers. To set up the charger, set the pot to midway, turn on the charger and then connect a battery to it`s...
Temperature Controlled NICD Charger IC LM311
This circuit is for a temperature controlled constant current battery charger. It works with NICD, NIMH, and other rechargeable cells. The circuit works on the principle that most rechargeable batteries show an increase in temperature when the cells becomes fully charged. Overcharging is one of the main causes of short cell life, hot cells pop the
Lithium Ion Lithium Poly Charger by LM317
The above circuit will charge any 2-cell * Li-Ion battery pack. Maximum current is about 650 milliamps. The circuit is designed for batteries of 900mah or higher. Note this circuit is NOT for Li-Metal batts (i. e. Duralites). Power source can be a 12v Gell cell (Power panel), or can be powered by a car`s cigarette lighter. I use an old 12v DC wall
Car Battery Charger12V circuit and explanation
All car batteries have required a 12v battery charger. And this is also true of Marine, RV and Power Sports batteries. The high efficiency lead acid type batteries available today require more efficient charging techniques. The most important factors in the life of your battery, the battery charger is the most valuable tool in saving the life of y
IC Controlled Emergency Light with Charger Circuit Schematic Free With Explanation
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 overcharge protection. When mains is absent, relay RL2 is in deenergised state, feeding battery supply to inverter section via its N/C contacts and switch S1. The inverter section
Simple Lead-Acid Battery Charger Circuit
The circuit diagram of lead acid battery charger has been described here. The core part of this circuit is the IC LM 317.
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...
DIY HV Variable Capacitor
DIY PMA Alternator Plans
Digital Signal Integrity