Standby battery circuit

Welcome back to Free circuit dot com ,today i would like to show you with simple circuit that will find many applications as emergency power supply for low power requirements. It consists of a transformer, a rectifier bridge and an electrolytic capacitor followed by a zener, which controls a transistor in serial order. The output is stabilized to + 7.5V. The spare battery 7.5V, in series with D7, floating on the edges of the exit points, ready to take in case of failure (interruption), the main supply. The voltage drop at the edges of D7, will reduce the output voltage from the battery voltage to about 7V. The R3 has a special function during the operation of main power lets a small stream flows to charge the empty data slowly or maintain an already charged battery. It is right that the resistance can be found by dividing the voltage difference between the zener D6 and battery, to secure a stream of leaks, which can amount to some 0,7 milliamps.

Electronic Part List

R1=1K2
R2-3-4=680R
R5=15K
R6=10K
R7-8-9-10=1K
IC1=LM324
D1=5V6 /0.5W Zener
D2-3-4-5=LED
RV1=10K trimmer

battary mornitor circuit

This circuit is used to monitor the battery voltage to display a dual-colored LED status of the battery to. If the LED “green”battery voltage exceeds 11.9 volts. If the yellow LED, battery voltage 11.9 to 11.5 volts. If the LED is “red” If the battery voltage below 11.5 volts. You can of course change the trigger points by the trimmer resistors and / or changing the value of the resistors in the divider.

 A dual op amp is used as a comparator. The green LED on the board, until the voltage exceeds 11.5 volts. The red LED illuminates when the voltage falls below 11.9 volts to the circuit. Therefore, in the 11.9 to 11.5 volts, both LEDs are on, producing a slightly yellow color. When the voltage falls below 11.5 V, the green LED, and now only the red LED flashes to indicate low voltage.

Electronic Parts List

R1=1K2
R2-3-4=680R
R5=15K
R6=10K
R7-8-9-10=1K
IC1=LM324
D1=5V6 /0.5W Zener
D2-3-4-5=LED
RV1=10K trimmer

 Is recommended that multi-shaper for V1 and V2. Muti-trimmer makes it much easier to trigger points to make as a less expensive single-turn trimmer. The trimmer can be completely eliminated if you have access to a range of 1% resistors and has had calculated carefully. You would also want to provide more accurate reference voltage as the common 78L05 regulator.

Voltage low warning circuit

Come again for voltage low warning circuit ,You can apply in your car to check voltage.
The same circuit can be used as an indicator of low voltage alarm when 10 volts Zener diode replaced by a Zener 1N5233B 6.2 volt.

The connection pin 4 of the LM339 and two resistors instead of 10K level sensor.
Connect a 1K resistor in the output of 12 volts (pin 3 of LM339) and a 10K resistor to ground (pin 12 of LM339). Set potentiometer reference voltage 0.5 * Low operating voltage of the street, the output voltage of 5 volts pot , If you travel a circuit with 10 volts. You can reduce the calculation of delay exceeds the threshold of 6.2 volts instead of 10 volts and current, if the index you want to shorten.
Electronic Part
R1, R3 1K 1/4W Resistor
R2 5K Pot
U1 LM339 Op Amp IC
D1 1N5233B Zener Diode
D2 LED
BZ1 Piezo Buzzer

Low voltage warning beeper circuit

Welcome back to Free circuit dot com for today we have the electronic circuit,This circuit is an alarm circuit for low battery status. It gives an audible and visual low voltage 12V battery powered devices. If the battery voltage exceeds the limit set (typically 11V), the circuit is idle. If the battery voltage must be below the setpoint, the LED and the speaker will beep periodically to warn of the impending loss of power punches. The circuit was designed for monitoring solar energy systems, but it can also be useful for automotive and other 12V.

How does it work?
U2 has a market regulated 5V voltage reference. U1 is wired as a comparator compares the voltage fixed 5V regulated voltage at the wiper of VR1, which is proportional to the 12V. If delivery is below the setpoint, the output of U1 goes low, turning on Q1 and food for the beep and the LED.

The acoustic signal consists of U4, a tone generator, and U3, a pulse generator with low duty cycle. The tone can be varied by adjusting R7, the beep rate be changed by adjusting R5. A small amount of hysteresis is provided by R1 and the current through LED1 and the beeper, which separates the points on and off the circuit.

U2 has a market regulated 5V voltage reference. U1 is wired as a comparator compares the voltage fixed 5V regulated voltage at the wiper of VR1, which is proportional to the 12V. If delivery is below the setpoint, the output of U1 goes low, turning on Q1 and food for the beep and the LED.

The acoustic signal consists of U4, a tone generator, and U3, a pulse generator with low duty cycle. The tone can be varied by adjusting R7, the beep rate be changed by adjusting R5. A small amount of hysteresis is provided by R1 and the current through LED1 and the beeper, which separates the points on and off the circuit.

Beeper use low voltage battery
Connect the circuit to the 12V source you wish to attend. Turn on S1, if the battery voltage exceeds the set value, nothing should happen.

If the battery voltage drops below the set value, the LED light and a buzzer will periodically speaker. If the beep is annoying, turn off S1. Make sure the battery fast charge, over discharge, the life of most rechargeable batteries shorten.

motorcycle battery charger circuit

Ordinary car battery chargers are simple and inexpensive devices that continuously charge the battery with a pace few amps, for the time the device is ON. If the holder does not close in time the charger, the battery will overcharge and electrowinning capacity will be lost by evaporation or likely to be destroyed elements. The charger circuit overcomes these defects. Electronically controls the battery charge and has a feedback control circuit, causing the battery to charge a maximum rate until fully charged. When fully charged, lights up a red Led (LD2).

    The charger is designed to charge batteries of 12V, only. What should be paid by whom built the circuit, are the cables connecting the transformer to the circuit and then the battery should be high profile, so that heat when it passes through the current load and also not cause voltage drop in the path of current through them.

Setting.

When construction is finished turn the TR1 in place zero value, then the following settings-control.
1] check without connecting the battery, that both LED’s light up.
2] Connect a car battery charger. Check that the LD2 is off and that a current (typically 2 until 4 A), flows to the battery.
3] Turn the TR1 and check that the LD2 can turn and charge current to cut
4] Turn the TR1 to null value and charge the battery using the standard technique hydrometer (if not available, use a battery in good condition and fully charged).

Turn carefully so that the TR1 LD2 begins to turn and charge current drops to a few hundred mA. If TR1 installed correctly then the next load will see the first LD2 will start to flicker, and charging the battery. When fully charged the battery then the LD2 will turn on fully.

To TR1 no longer needs another adjustment. The Q1 is connected in series with the circuit of the battery and can be fired from the circuit R3-4 and LD2. The battery terminal voltage is obtained from the circuit R2, C1, TR1, D2 and activates the Q2 when the voltage terminals exceeds the value we are striving to TR1.

When an uncharged battery put on charge the terminal voltage is low. under this situation the Q2 turn off and Q1, fired in each half cycle of the circuit R3-4, LD2. The Q1 functions as a simple rectifier. While charging the battery, the terminal voltage increases. If the terminal voltage rises above the level that we have set to TR1, then shifts the Q2 gate drive of Q1, it turns off, stop giving power to the battery and lights LD2, showing us that the loading is complete. The Q1 and the bridge rectifier GR1, should be placed on a good heatsink for proper cooling. The M1 is an ammeter DC 5A, so we can monitor the charging current. Optionally can be placed a voltmeter in parallel with the poles of the battery should have high input impedance, however, not affect the circuit measuring device.

Power source checking and alarm

I have most of electrical project for add the power failure indicator circuits want a separate power supply for themselves. But this power supply alarm circuit presented here want no additional supply source.

 It employs an electrolytic capacitor to store adequate charge to power the alarm circuit, an alarm will sound for a reasonable period if the power fails. This circuit can be used as a signal for the power supply ranging from 5V to 15V.

To calibrate the circuit before connecting to the power supply (5 to 15V) and then vary the potentiometer VR1 until the buzzer goes from on to off. Whenever the lack of power, resistance R2 of the base of the transistor and low saturated moves, turning the buzzer.

How does the circuit
Circuit consists of five components:

R1= 1Kohms D1= 1N4001 T1= 220V/17V 4A Transformer
R2= 1.2Kohms D2= 6.8V 0.5W zener LD1= Green LED
R3= 470 ohms TR1= 4.7Kohms  trimmer LD2= Red LED
R4= 470 ohms Q1= BTY79 or similar 6A SCR M1= 0-5A DC Ampere meter
R5= 10Kohms Q2= C106D  SCR S1= 10A D/P On Off Switch
C1= 10uF 25V GR1= 50V 6A Bridge Rectifier F= 5A Fuse

  Circuit does not turn on until the battery is connected to the terminals, as shown in the picture. (Assuming the pressure switch is connected to a circuit where there is a completely discharged battery started.)
This action turns on the PNP transistor in the “Turn On” block. Resistance between the collector-emitter terminals, and LED lights.
Journey to the bottom of the circle passing through the railway signal diode, gate-cathode junction of SCR and two parallel resistors 1R8. Therefore, it shines.

Must use the AC PLUG PACK
Before we go further, working circuit pack into the AC outlet. There must be an AC power supply, as we do not want to be present at all the capacitors on the power flow rail, because it allows a very high charging current and possibly damage the SCR.
DC does not let you turn on the SCR, it will shut off flow through to zero.

Circuit is half-wave rectifier!
Circuit is actually a half-wave rectifier. It only charges the battery in each half cycle. Plug-pack, not the way it leaves a residual flow in the transformer core and leads him overheat. But that is a disadvantage of the circuit.
SCR switches in each half cycle and flows into the battery.
Voltage through two resistors 1R8 (parallel development), and this voltage is fed into the electrolyte-47U. Is charging and turns the BC547 transistor.
Transistor turns off SCR gate voltage and robs the SCR. 47U energy channels of the transistor for a short time, but could not maintain the transistor.
Transistor switches and switch SCR and provides further impetus to the current battery.
Since the battery is charging, the voltage increases and it is followed by “Voltage Monitor Block.
The circuit is very complex and able to look at the operation is to check the top rail as a fixed rail and increasing the battery voltage, rail is the negative battery terminal is connected, pushed down.
So you can see how to “Turn On” transistor is switched on and a “voltage monitor” components to create voltage drops on each of them.
“Voltage Monitor” component consisting of transistors and Zener diode and resistor 8k2, 1k pot 1K5 resistor, 150R resistor and diode signal.
Signal-emitting diode is actually part of the flashing circle and discuss the operation later.
When the battery voltage rises to 13.75 volts, all resistance in “voltage test systems, will have a voltage drop, which corresponds to the resistance of resistance. Diode is a constant 0.7 V above them.
Voltage at the wiper of banks will be about 3.25V and 10V, the voltage across the Zener. This leaves 0.6V between the base and the producer of the transistor voltage monitor.
This voltage is sufficient to turn transistor.
When the monitor voltage transistor switches, it robs the “Turn On” transistor base-emitter voltage and the circuit is turned off.
SCR has only two states: ON and OFF.
By the mid-cycle when it is turned on, battery power and high pulse current is limited to the ability to plug-pack.
There are no capacitors to enable very high current pulses are delivered, and it is fortunate, because the SCR is only 0.8 amps drive, but it will take 10 amps to increase the half-cycle.
Whenever the SCR is in the lead during the mid-cycle operation initiated, remains in heat conduction, the voltage supplied plug pack will drop to zero. That is, when the SCR turns off.
If the plug-pack delivers a negative voltage on the top rail and a positive voltage to the lowest rail, the SCR is triggered into the conduction band and none of the components in the circuit provides power to the battery. SCR provides a couple of Half-stream and then turns to several cycles. This is how the average current supplied by the battery is controlled.
The circuit is designed to deliver approximately 300-400 mA average charging current. The actual value is set resistors 1R8.
If the battery is fully charged, the LED will blink.
Flashing is made of resistance 2K2 and 47U (connected to a voltage monitor section).
That the battery is connected through diode 47U, charging 150R BC557 transistor and a signal diode to the negative terminal of the battery.
If the battery is fully charged, the monitor turns on and turns off the power supply section of “Turn On” section.
This eliminates stress on the positive side of the 47U and the positive side, a negative rail through resistor 2K2. This allows the negative side of 47U and 150R resistor is enabled, distorted, negative despite the presence of light rail, because the diode is reverse-drop.
This keeps the circuit in the “off” state, as part of the voltage monitor provides an additional voltage across the battery and it thinks it is “over-burdened.

Car Battary Charger Circuit

The charger charges quickly and easily on all lead-acid batteries. The charger delivers full current, decreases until the current from the battery to 150 mA. At this time, a lower voltage to complement and support more load. If the battery is fully charged, the circuit stops and lights a LED indicates that the cycle is complete.
 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 at the terminals of the battery.
If the battery is not charged, shows the ammeter reading 3.1 amps.
If the battery is fully charged the ammeter reads zero or nearly zero, after which the battery must be removed from the
Charger.
The circuit is a full-wave rectifier with two diodes for rectification. The capacitor is used for smoothing.
I think the circuit works fine without the capacitor since the battery itself acts like a capacitor BIG. But if the
12V power supply circuit (such as a battery eliminator), the capacitor must be present.
Care must be taken to reverse the + and – terminals while connecting to the battery.

voltage comparator circuit

In the circuit having a voltage quad comparator (LM339) is used as a simple bar graph meter to indicate the state of charge 12-volt lead-acid battery acid. A 5 volt reference voltage is in each of the (+) inputs of four comparators and the (-) inputs are connected, each point is connected to a voltage divider. The LED lights up when the voltage at the negative (-)-input exceeds the reference voltage. Calibration can be by adjusting the 2K potentiometer so that all four LEDs illuminate when the battery voltage is 12.7 volts indicates a full charge with no load on the battery is done. At 11.7 volts, the LED should be made, and shows an empty battery. Each LED is a change of about 25% charge or 300 millivolts, so that 3 LEDs indicate 75%, 2 LEDs indicate 50%, etc.

The actual voltage on the temperature and battery type from, battery wet gel battery, etc . For more information on battery care.

battery charger circuit with IC regulator

The circuit is the elementary 6V 1A power supply circuit using IC regulator 7808. The 7808 three-terminal positive voltage regulator is available in the TO-220/D-PAK package build them useful in a wide range of applications.

The IC 7808  employs internal current limiting, thermal shut down and safe operating area protection, doing it essentially indestructible. If proper heat sinking is provided, it can deliver over 1 ampere output
current.

Automatic Ni-Cd battery charger circuit

Although this circuit looks quite impressive, and perhaps a little “difficult, it is not difficult to understand. The circuit must be connected to a DC voltage between 16.5 and 17.5 volts max, otherwise the CMOS IC will be defective. Because I do not want to design a separate power supply for this circuit I connected my full Power Supply adjustable bench top.
   
   
   
First connect one “is cost-”-9-volt nickel-cadmium batteries for proper connections. Then connect it to power. At the 1nF capacitor starts the two RS flip-flop formed by IC1a, IC1b, IC1c, IC1d, and pulls pins 3 and 10 ‘high’ and pins 4 and 11 ‘low’. The clock pulses generated by the freewheeling MULTIVIBRATOR IC4. IC4 frequency determined by 10UF capacitors, resistors CAP 220K and 100K.

The clock runs continuesly, but behind the counter, IC5 not count yet because pin 11 (master reset) is kept high. When the button “START” button is pressed, output pin 4 from IC1a goes up and prejudices tr4 rendered visible by the red LED (D9), who is still on. The NiCad is now discharged via this transistor and the resistance of 100 ohms.
The CAP 10K (right graph) is adjusted so that when the battery voltage drops below 7 volts, the production of IC3 goes low and the output pin 11 of IC1a HIGH. HTE while output pin 10 of IC1d goes low and the red LED turns off.

usb charger circuit

This change highlights series and parallel connections of the past,
allowing an increase in the number of devices that can use a Personal computer.
This simple circuit USB charger low-dropout regulator (LDO) has use IC LT1085 .
One way to use the USB power is the battery . Since many mobile devices such as MP3 players and PDAs to exchange information with computers, peripherals convenience is significant when the battery and the exchange of data takes place simultaneously on cable. The combination of USB and battery function leads to a series of “autonomous” from devices such as webcams lid, all connected to a PC or not. In many cases, it is no longer required, a clumsy adapter or wall wart. “
The battery charger from the USB can be complex or simple as you are exempt from the requirements of the USB device.
Design influence on the choice Chorus typical “cost”, “size” and “weight”.
Others following considerations:
1) the speed of a device with a battery is compatible with all functions, if a USB port
2) the time may be granted to the battery
3) power in the USB budgeting limits and
4) the need for the power supply.

Car Battery Charger

Electronic Part List

1. R1  500 Ohm 1/4 W Resistor 
2. R2  3K 1/4 W Resistor 
3. R3  1K 1/4 W Resistor 
4. R4  15 Ohm 1/4 W Resistor 
5. R5  230 Ohm 1/4 W Resistor 
6. R6  15K 1/4 W Resistor 
7. R7  0.2 Ohm 10 W Resistor 
8. C1  0.1uF 25V Ceramic Capacitor 
9. C2  1uF 25V Electrolytic Capacitor 
10. C3  1000pF 25V Ceramic Capacitor 
11. D1  1N457 Diode 
12. Q1  2N2905 PNP Transistor 
13. U1  LM350 Regulator 
14. U2  LM301A Op Amp 
15. S1  Normally Open Push Button Switch

Car Battery Charger

Part List

C1 1 6800uF 25V Electrolytic Capcitor 
T1 1 3A 15V Transformer 
BR1 1 5A 50V Bridge Rectifier 10A 50V Bridge Rectifier
S1 1 5A SPST Switch 
F1 1 4A 250V Fuse