The circuit details are based on european standards: 120E, 150E, etc. The ‘E’ just stands for Ohms so 120 ohm, 150 ohm. The original circuit specified the HEF type of CMOS IC’s that are not readily on the market in most of worldwide country. So just get any other kind of CMOS chip like the MC4011, MC4020, MC4047 from Motorola. Any other type will work fine too. The BC548B is replaceble by a NTE123AP (NOTE: ensure it’s the ‘AP’ type, the typical NTE123A is a total different transistor), ECG123AP, and also the 2N3904 will be work. Watch for the proper pin locations because the BCE may be reversed with this european type. The LM317T is a TO-220 type and replaceble with a ECG956 or NTE956. The LM339N could be changed using a ECG834 or NTE834

Even though this battery charger circuit looks pretty impressive and perhaps a bit complex, it’s actually not difficult to understand. The circuit needs to be hooked-up to a DC supply voltage of between 16.5 and max 17.5 volt, otherwise the CMOS IC’s will go defective. Simply because I didn’t feel like to build a seperate power supply for this circuit, I connected it to my fully variable bench top power supply.

To start with, we connect a ‘to-be-charged’ 9-volt nicad battery to the suitable connections. Then hook it up to the power supply. Upon connection the 1nF capacitor starts up the two RS Flip-Flops formed by IC1a, IC1b, IC1c, IC1d, and pulls pins 3 and 10 ‘high’ and pins 4 and 11 ‘low’. The clock pulses are created by the free-running multivibrator IC4. IC4’s frequency is determined by the 10uF capacitors, the 220K resistor and the 100K trimpot. The clock runs continuesly but the counter behind, IC5, is not counting however because pin 11 (the master-reset) is kept high. When the ‘START’ button is pressed, output pin 4 from IC1a goes high and biases TR4, which is made visible by the Red LED (D9) which remains lit. The NiCad is now becoming discharged via this transistor and also the 100 ohm resistor.The 10K trimpot (at the right of the diagram) is adjusted in such a way that when the battery voltage dips below 7 volt, the output of IC3 goes LOW and the output pin 11 of IC1a HIGH. At hte same time the output pin 10 of IC1d goes LOW, and also the red LED turns off.

Because output pin 11 went HIGH the green LED (D8) lights up and at the exact same time the voltage level rises causing the battery to be charged. The charge-current is determined by the 120 ohm, 150 ohm, and the trimpot of 1K, at the right side of IC2. Really we could have used 1 resistor, but the output voltage of different brands for IC2 may differ, by about 1.25 volt.

Simply because the charging present is devided by value of the resistors, with the trimpot the current could be adjusted to the correct value of your own 9-volt NiCad. (In my case, the battery is a 140 mA type, so the charge present should be adjusted for 14 mA (c/0.1).

At the exact same time the LOW of output pin 10 from IC1d starts the counter of the clock. On pin 9 of IC5 appear pulses which light up the red LED. This is implemented for two factors, the clock-frequency can, with the 100K trimpot, be adjusted to the correct value; the red LED has to come ON for 6.59 seconds and for the same duration going OFF and except for that fact the green LED, who indicates the charge current, can be checked if the total charge-time is correct.When the counter has reached 8192 pulses ( x 6.59 = 53985.28 sec = 14.99 hours) the output pin 3 of IC5 goes high again, transistor Tr1 activates and resets the two flip-flops to the start position.

The charging process stops and goes over to trickle charge via the 10K resistor and the D2 diode and keeps the battery topped-up.The adjustments of the project are truly extremely simple and nothing to be concerned about. Turn the walker of the 10K pot in the direction of the 12K resistor, ground connection point of 10K resistor/diode D2, like the adjustment pin of IC2, apply a voltage of 7-volt to the battery connection terminals, switch the power ON and slowly turn the pot backward until the greeen LED starts to light up. Switch OFF the power and take away the connections you created to make the adjustment.Insert an amp-meter between the battery and also the output connection and again switch the power ON. The battery will, in case it is not totally empty, totally discharged (to a secure level) and as soon as the 7 volt margin is reached goes over to the charge cycle. The charge present is at this time adjusted via the 1K trimpot (which is connected in series with the 150 Ohm resistor and in parallel with the 120 ohm resistor) accurately to the desired value.

Addendum: It’s strongly suggested to include little 100nF ceramic capacitors over the power supply lines feeding Every CMOS IC to keep feasible interference to a negliable value.

The post Automatic 9V Battery Charger appeared first on Circuit Schematic Diagram.

The lamp L1 will be light brightly and the LED will be out when the battery is low and battery charging in progress, but the LED is very bright and the lamp L1 dim when the battery is almost ready to use (charge complete). L1 must be a bulb lamp rated for the current you want (usually the battery capacity divided by 10).

The diode D1 should be at least 1 A, and Z1 is a zener diode 1 W with a voltage determined by the fill-charge battery voltage minus 1.5 V. When the battery is fully charged, the circulatory flow around the battery capacity divided by 100 mA.

The supply voltage can be from 12V power supply or from 12V lead acid battery from your car via cigarette lighter socket.

The post NiCAD Battery Charger with Current and Voltage Limiting appeared first on Circuit Schematic Diagram.

Components List:

Resistor: 1 K Ohm, 68 Ohm, 2 K Ohm, Potensiometer 10K Ohm
Diode: IN4001, 2x Zener IN752
Transistor: 2N2219, 2N2222

This NiCAD battery charger circuit charges the battery at 75 mA until the battery is charged, then it reduces the current to a trickle rate. It will fully recharge a dead/unpowered battery in 4 hours and the battery can be left in the charger indefinitely. To set the shut off point, connect a 270 ohm / 2 Watt resistor across the charge terminals and adjust the potensiometer for 15.5V across the resistor.

The input voltage for this battery charger circuit is 24VDC, you may use a general purpose power supply or 24V lead acid battery from your car.

The post 200mA/Hour – 12V NiCAD Battery Charger appeared first on Circuit Schematic Diagram.

Charging is accomplished with a constant current of 60 mA for AA cells to a cutoff of 2.4V per cell, at which point the charge must be terminated.

The charging system shown is designed for multi-cell battery pack of 2 to 6 series connected cell or series/paralel arrangements. It is essential that all cells assembled in the pack are at an identical state-of-charge (voltage) before charging. the maximum upper cut-off voltage is 15.6V (6×2.6V). The ICL7665 from Maxim is a voltage monitor with dual over/undervoltage detection.

The post Lithium Battery Charger appeared first on Circuit Schematic Diagram.

This 6V and 12V car battery charger circuit can be automatically charged, quickly and correctly, 6V and 12V batteries. Circuit design is divided into two series of modules that are: power supply module and the main charger module containing the regulator modules and direct current amplifier module.

How the 6V and 12V Car Battery Charger Works

A key factor in the success of the operation of the circuit is the use of good quality transformer [T1]  with very good insulation and resistance to short circuits. The Q1 through divider R1-2, of TR1 and R4, functions as a regulated current source. The current through R9 drives power transistors Q5-6, where amplified approximately x2000 times. In an unloaded car battery voltage is about 6V to 8V. With these conditions, the charge current is about 1.2A [regulated by TR1]. When the battery is charging slowly, gradually increases the voltage at its ends. 7V to enter into the D1 conducts. As the battery voltage increases, the voltage decreases at the ends of R3 Q1 made the most conductive. This continues until the current reaches about 6A. Then by means of the voltage drop across R10, is made conductive to Q4. The excess current to the base of Q5 to ground, keeping the load current constant. When the battery is fully charged [14.4V] activated in parallel to the circuit battery, consisting of R6, D8, D2 to D6. At the same time illuminates the D8 indicating that the battery has been fully charged. Simultaneously Q2 is conducting because the voltage drop on R6. The Q3 is conductive and grounded part of the stream at the base of Q5. When the voltage across the battery reaches approximately 15V current at the base of Q5 is very small, so to stop charging the battery. Diodes D5-6 protect the circuit from accidentally installing the battery or short circuits of long duration. The diode D4 protects the circuit from wrong positioning of the battery terminals. Then D9 Led lights showing connection error [ERROR]. Closing switch S2 short the diode D2 [6.8V], now we can charge 6V battery.

6V and 12V Car Battery Charger Component List

6V and 12V Car Battery Charger  Adjustment

The initial charge current should be adjusted via the TR1 to 1.2A. The adjustment can be done with a 6V battery. Connect in series with the battery a current [maximum 10A]. If there is 6V battery is short-circuited through the ammeter the charger terminals and adjust the TR1 current to 1.2A. When setting the switch S2 should be in the position of 12V, i.e. open. Particular attention should be paid to the accuracy of the diodes D2 and D3 because they protect the battery from overcharging. If the differential voltage is 100mV to go to consider them as acceptable. If you encounter difficulties in the current setting and the TR1 is not enough, you can change the value of the resistor R4, to measure charge current 1.2A. The two parallel resistors constituting R10, should be placed at a distance from the printed and Q5-6, because heated. The bridge B1 and Q5-6 be mounted on heatsink having insulated electrically from this with suitable mica silicone. The bridge B1 and the board in which the circuit is mounted must be connected with short and thick cables, especially where the current is large. lines are also printed on must have the appropriate width [in the project are shown in thicker line]. The construction should be done in a nice metal box, suitable dimensions so there is good ventilation. The construction requires the expertise.

WORK WITH BATTERIES REQUIRE HIGH ATTENTION IN HANDLING BECAUSE THERE IS ALWAYS A RISK OF EXPLOSION.

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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 this post is capable of producing a power of 5 watts. At full sunlight, the solar cell outputs 16.5V. It can deliver a current of 300-350 mA.

How the circuit works?

The working of the circuit is quite simple. The output of the solar panel is fed via diode 1N5402 (D1), which acts as a polarity guard and protects the solar panel. An ammeter is connected in series between diode D1 and fuse to measure the current flowing during charging of the batteries. As shown in Image #1, we have used an analogue multimeter in 500mA range. Diode D2 is used for protection against reverse polarity in case of wrong connection of the lead-acid battery. When you connect wrong polarity, the fuse will blow up.

For charging a lead-acid battery, shift switch S1 to “on” position and use connector “A.” After you connect the battery, charging starts from the solar panel via diode D1, multimeter and fuse. Note that pulsating DC is the best for charging lead-acid batteries. If you use this circuit for charging a lead-acid battery, replace it with a normal pulsating DC charger once a week. Keep checking the water level of the leadacid battery. Pure DC voltage normally leads to deposition of sulphur on the plates of lead-acid batteries.

For charging Ni-Cd cells, shift switches S1 and S3 to “on” position and use connector “B.” Regulator IC 7806 (IC1) is wired as a constantcurrent source and its output is taken from the middle terminal (normally grounded). Using this circuit, a constant current goes to Ni-Cd cell for charging. A total of four 1.2V cells are used here. Resistor R2 limits the charging current.

For charging Li-ion battery (used in mobile phones), shift switches S1 and S2 to “on” position and use connector “C.” Regulator IC 7805 (IC2) provides 5V for charging the Li-ion battery. Using this circuit, you can charge a 3.6V Li-ion cell very easily. Resistor R3 limits the charging current. Image #2 shows the circuit for a small LED-based lamp. It is simple and lowcost. Six 10mm white LEDs (LED2 through LED7) are used here. Just connect them in parallel and drive directly by a 3.6V DC source. You can use either pencil-type Ni-Cd batteries or rechargeable batteries as the power source.

Assemble the circuit on a general purpose PCB and enclose in a small box. Mount RCA socket on the front panel of the box and wire RCA plug with cable for connecting the battery and LED based lamp to the charger.

With this circuit, you can save on your electricity bills by switching to alternative sources of power.

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This is the cell phone shield circuit which can be used as mobile charger. Give protection to your cell phone from unexpected use or theft working with this easy circuit. It is able to produce a loud chirping sound when someone tries to take away the mobile handset. The added function is that the circuit also operates as being a mobile charger.

The circuit is powered by a step-down transformer X1 with rectifier diodes D1 and D2 and filter capacitor C1. Regulator IC 7812 (IC1) together with noise filter capacitors C2 and C3 gives regulated power source.

The cell phone shield circuit uses two NE555 timer ICs: One as being a very simple astable multivibrator (IC2) and then the 2nd as being a monostable multivibrator (IC3). The astable multivibrator has timing resistors R1 and R2 but no timing capacitor since it operates with stray capacitance. Its pins 6 and 2 are directly joined to a safeguarding shield built up of 10cm?10cm copper-clad board.

The inherent stray capacitance of the circuit is enough to supplied an output frequency of about 25 kHz with R1 and R2. This arrangement gives better sensitivity and allows the circuit with hand capacitance effect. Output pulses from the oscillator are immediately assigned to trigger pin 2 of the monostable multivibrator. The monostable utilizes a low-value capacitor C6, resistors R3 and preset VR1 for timing.

The output frequency of the monostable multivibrator is altered utilizing preset/trimmer VR1 such that it is slightly less than that of the astable multivibrator. This makes the circuit standby, as soon as there is no hand capacitance present. So in the standby mode, the astable”s output is going to be low. This tends to make the trigger input of monostable become low and output become high.

The warning indicator buzzer and LED1 are joined such that they come to be active only when the output of the monostable multivibrator sinks current. During the standby state, the LED1 continues to be “off” and also the buzzer is silent. As someone attempts to take the cell phone from the defending shield, his hand comes close to the shield or makes contact with the shield, which introduces hand capacitance within the circuit. Because of this, the astable”s frequency changes, which makes the trigger pin of the monostable become low and its output oscillates. This generates chirping sound from the buzzer and also makes the LED1 blink.

The circuit can even be utilized as being a mobile charger. It delivers output of 6V at 180 mA through regulator IC 7806 (IC4) and resistor R5 for charging the cell phone. Diode D3 defends the output from polarity reversal.

The circuit could be wired on a general PCB. Enclose it inside a appropriate case with provision for charger output leads. Produce the protective shield making use of 10cm?10cm copper-clad board or aluminium sheet. Hook it up towards the circuit working with a 15cm plastic wire. Leads of all capacitors ought to be short.

Fine-tune VR1 little by little working with a plastic screwdriver until eventually the buzzer stops sounding. Get the hand nearby to the shield and fine-tune VR1 right up until the buzzer sounds. With trial-and-error method, set it up for the highest level of sensitivity such that as shortly the hand comes close to the shield, the buzzer begins chirpring and also the LED blinks. As an alternative to applying the copper cladding for shield, a metallic cell phone holder can be utilized as being the shield.

The post Cell Phone Shield with Charger appeared first on Circuit Schematic Diagram.

Components List:

* Resistors are carbon type, 1/4 watt, 5% tolerance, unless otherwise indicated.

Circuit explanation:
This circuit requires a regulated 10V-DC front end capable of supplying 2 Amps electric current, you should build this kind of power supply first. Begins the charge period at 240mA and at full charge switches automatically to a float condition (trickle charge) of 12mA. The capacitors should be the ceramic 50V (or greater) model.

Switching transistor T1 is an NPN, Si-Power Output/SW, with a TO-220 case and can be changed by using a appropriate substitute such as the NTE291, ECG291, etc. Timer/Oscillator U1 is a 8-pin NE555V and can be changed with a NTE955M or ECG955M. Resistors R4, R5, R6, and R7 are 1% metal film types. They may not be obtainable at your nearby Radio Shack/Tandy retailer and need to be ordered in. Try Electro-Sonic or Newark Electronics supply stores.

NOTE: This circuit is only designed for 6-volt, 1.2Ah Gel Cell type batteries!

The post 6V Gel Cell Battery Charger appeared first on Circuit Schematic Diagram.

This circuit provides an initial voltage of 2.5 V per cell at 25 ? to quickly charge the battery. The charging current decreases as the battery is charging, and when the current drops to 180 mA, the charging circuit reduces the output voltage of 2.35 V per cell, leaving the battery in a fully charged state. This lower voltage prevents the battery from overcharging, which would shorten its life.

The LM301A compares the voltage drop across R1 with an 18 mV reference set by R2. The comparator’s output controls the voltage regulator, forcing it to produce the lower float voltage when the battery-charging current, passing through R1, drops below 180 mA. The 150 mV difference between the charge and float voltages is set by the ratio of R3 to R4. The LEDs show the state of the circuit.

Temperature compensation helps prevent overcharging, particularly when a battery undergoes wide temperature changes while being charged. The LM334 temperature sensor should be placed near or on the battery to decrease the charging voltage by 4 mV/? for each cell. Because batteries need more temperature compensation at lower temperatures, change R5 to 30 ?for a tc of -5 mV/? per cell if application will see temperatures below -20?.

The charger’s input voltage must be filtered dc that is at least 3 V higher than the maximum required output voltage: approximately 2.5 V per cell. Choose a regulator for the maximum current needed: LM371 for 2 A, LM350 for 4 A, or LM338 for 8 A. At 25? and with no output load, adjust R7 for a V_OUT of 7.05 V, and adjust R8 for a V_OUT of 14.1V.

The post Lead-Acid Battery Charger appeared first on Circuit Schematic Diagram.

Today, a lot of handheld gadgets (for example: portable reading lamps, smartphones, tablets, ipod) utilise this resource of the USB port to recharge their battery pack using the support of an internal circuitry. Typically 5V DC, 100mA electric current is needed to satisfy the input electrical power demand.

The above diagram shows the circuit of a versatile USB power socket that properly converts the 12V battery voltage into stable 5V. This car cigar lighter to USB circuit can make it possible to power / recharge any USB power-operated device. It work with in-dash board cigar lighter socket of the car.

The DC supply presented from the cigarette lighter socket is fed to an adjustable, three-pin regulator LM317L (IC1).

Capacitor C1 buffers any disorder in the input supply. Resistors R1 and R2 regulate the output of IC1 to constant 5V, that is accessible at the “A” type female USB socket. Red LED1 signifies the output condition and zener diode ZD1 acts as a protector against excessive voltage.

Assemble the circuit of car cigar lighter to USB power socket on a general purpose PCB and enclose inside a slim plastic cabinet as well as the indicator and USB socket. Whilst wiring the USB outlet, make sure proper polarity of the supply. For interconnection between the cigar plug pin as well as the device, use a long coil cord as shown in second image.

Here the Pin configuration of LM317L:

Download this car cigar lighter to USB circuit in PDF Version:

USB Power Socket Project

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