Showing posts with label battery. Show all posts
Showing posts with label battery. Show all posts
Tuesday, December 24, 2013
Super Universal Battery Charger Circuit Diagram
The Super Universal Battery Charger Circuit Diagram output voltage is adjustable and regulated, and has an adjustable constant-current charging circuit that makes it easy to use with most NiCad batteries. The charger can charge a single cell or a number of series-conoected cells up to a maximum of 18 V.
Power transistors Ql and Q2 are conoected as series regulators to control the battery charger`s output voltage and charge-current rate. An LM317 adjustable voltage regulator supplies the drive signal to the bases of power transistors Ql and Q2. Potentiometer R9 sets the output-voltage level. A current-sampling resistor, R8 (a 0.1-!J, 5-W unit), is conoected between the negative output lead and circuit ground. For each amp of charging that flows through R8, a 100 mV output is developed across it.
The voltage developed across RS is fed to one input of comparator U3. The other input of the comparator is connected to variable resistor RIO. As the charging voltage across the battery begins to drop, the current through RS decreases. Then the voltage feeding pin 5 of U3 decreases, and the comparator output follows, turning Q3 back off, which completes the signal`s circular path to regulate the battery`s charging current. The charging current can be set by adjusting RlO for the desired current. The circuit`s output voltage is set by R9.
Super Universal Battery Charger Circuit Diagram
Monday, September 30, 2013
9V DC Adapter With Battery Backup
With just a low cost DC adapter and the circuit described here it is possible to build a low cost stabilized, uninterruptable 9V supply. On the grounds of safety and economy, a simple unstabilized 12V D.C. adapter is used as the power source, a universal adapter with its output set to 12 V will do equally well. The output voltage of an adapter under low load conditions (up to approximately 1/3 of the rated output current) is over 15 V, even at the rated output current, there will be sufficient voltage to supply a 9 V voltage regulator. The rating of the DC adapter should be chosen according to the output current required at 9V. Common values are 300mA, 500mA and 1A.
The 9V voltage regulator used in this circuit has a built in thermal shutdown mechanism so that if too much current is drawn from the device, it simply turns off as it overheats and will not supply any current until the case temperature returns to normal. If the unit is intended to supply more than say 150-200mA then to prevent thermal shutdown it will be necessary to fit a heatsink to the voltage regulator. The rule of thumb used to calculate the size of heatsink is that you should be able to touch it during operation at maximum load, without burning you finger. When choosing the DC adapter, it is always better to select one with a higher current rating than is needed this will ensure that its output voltage is high enough to be able to also charge the 12V cells.
As long as mains voltage is on the DC adapter, the voltage across C1 will be higher than the voltage of the cells. Charging current will flow through R1 and D1 to the cells. Current also flows to the voltage regulator and out to the load connected at the output. Diode D2 in this situation will not conduct because the voltage at its cathode is greater than that at its anode When the mains voltage fails or is turned off, diode D2 conducts and current will now flow from the Nickel Cadmium cells to the voltage regulator, thereby automatically keeping the output voltage at 9V. The value of resistor R1 is chosen so that a charging current to the cells is not greater than 1/10th of the cells capacity (if the cells are rated at 1100mAh, the charging current must not exceed 110mA).
From the point of view of cell longevity it is better to reduce this charging current even further (1/20 or 1/50 C). When calculating this resistor, the value of the no-load voltage should be used. This will give the highest charging current. To calculate the charging current using R1 with a value of 180 Ω. The cells measure 13.8 V when fully charged and the no-load output voltage of the DC adapter is 17V. Charging current is given by the formula: (17V – 13.8V – 0.7V) / 180 = 13.9mA. Substituting the actual measured values in this formula will enable you to calculate the value of R1 to give the correct charging current for the cells.
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The 9V voltage regulator used in this circuit has a built in thermal shutdown mechanism so that if too much current is drawn from the device, it simply turns off as it overheats and will not supply any current until the case temperature returns to normal. If the unit is intended to supply more than say 150-200mA then to prevent thermal shutdown it will be necessary to fit a heatsink to the voltage regulator. The rule of thumb used to calculate the size of heatsink is that you should be able to touch it during operation at maximum load, without burning you finger. When choosing the DC adapter, it is always better to select one with a higher current rating than is needed this will ensure that its output voltage is high enough to be able to also charge the 12V cells.
As long as mains voltage is on the DC adapter, the voltage across C1 will be higher than the voltage of the cells. Charging current will flow through R1 and D1 to the cells. Current also flows to the voltage regulator and out to the load connected at the output. Diode D2 in this situation will not conduct because the voltage at its cathode is greater than that at its anode When the mains voltage fails or is turned off, diode D2 conducts and current will now flow from the Nickel Cadmium cells to the voltage regulator, thereby automatically keeping the output voltage at 9V. The value of resistor R1 is chosen so that a charging current to the cells is not greater than 1/10th of the cells capacity (if the cells are rated at 1100mAh, the charging current must not exceed 110mA).From the point of view of cell longevity it is better to reduce this charging current even further (1/20 or 1/50 C). When calculating this resistor, the value of the no-load voltage should be used. This will give the highest charging current. To calculate the charging current using R1 with a value of 180 Ω. The cells measure 13.8 V when fully charged and the no-load output voltage of the DC adapter is 17V. Charging current is given by the formula: (17V – 13.8V – 0.7V) / 180 = 13.9mA. Substituting the actual measured values in this formula will enable you to calculate the value of R1 to give the correct charging current for the cells.
Friday, August 9, 2013
Battery Powered Night Lamp
This circuit is usable as a Night Lamp when a wall mains socket is not available to plug-in an ever running small neon lamp device. In order to ensure minimum battery consumption, one 1.5V cell is used and simple voltage doublers drives a pulsating ultra-bright LED: current drawing is less than 500µA. An optional Photo resistor will switch-off the circuit in daylight or when room lamps illuminate, allowing further current economy. This device will run for about 3 months continuously on an ordinary AA sized cell or for around 6 months on an alkaline type cell but, adding the Photo resistor circuitry, running time will be doubled or, very likely, triplicates. IC1 generates a square wave at about 4 Hz frequencies. C2 & D2 form voltage doublers, necessary to raise the battery voltage to a peak value able to drive the LED.
Parts:
R1 = 1M
R2 = 1M
R3 = 47K
R4 = LDR
C1 = 100nF-63V
C2 = 220uF-25V
D1 = Ultra Bright 10mm LED
D2 = 1N5819 B1 = 1.5V Battery or AA Cell
IC1 = 7555 CMos Timer IC
Notes:
* IC1 must be a CMos type: only these devices can safely operate at 1.5V supply or less. * If you do not need Photo resistor operation, omit R3 & R4 and connect pin 4 of IC1 to positive supply. * Ordinary LEDs can be used, but light intensity will be poor. * An ordinary 1N4148 type diode can be used instead of the 1N5819 Schottky-barrier type diode, but LED intensity will be reduced due to the higher voltage drop. * Any Schottky-barrier type diode can be used in place of the 1N5819, e.g. the BAT46, rated @ 100V 150mA.
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Parts:
R1 = 1M
R2 = 1M
R3 = 47K
R4 = LDR
C1 = 100nF-63V
C2 = 220uF-25V
D1 = Ultra Bright 10mm LED
D2 = 1N5819 B1 = 1.5V Battery or AA Cell
IC1 = 7555 CMos Timer IC
Notes:
* IC1 must be a CMos type: only these devices can safely operate at 1.5V supply or less. * If you do not need Photo resistor operation, omit R3 & R4 and connect pin 4 of IC1 to positive supply. * Ordinary LEDs can be used, but light intensity will be poor. * An ordinary 1N4148 type diode can be used instead of the 1N5819 Schottky-barrier type diode, but LED intensity will be reduced due to the higher voltage drop. * Any Schottky-barrier type diode can be used in place of the 1N5819, e.g. the BAT46, rated @ 100V 150mA.
Tuesday, July 9, 2013
Simple 9 V Battery Replacement
This circuit was originally designed to power a motorcycle intercom from the vehicle supply system. This type of intercom, which is used for communication between driver and passenger, generally requires quite a bit of power. In order to improve intelligibility there is often elaborate filtering and a compander is sometimes used as well. The disadvantage is that a battery doesn’t last very long. You could use rechargeable batteries, of course, but that is often rather laborious. It seems much more obvious to use the motorcycle power supply instead.
9-V Battery Replacement Circuit Diagram
A 9-V converter for such an application has to meet a few special requirements. For one, it has to prevent interference from, for example, the ignition system reaching the attached circuit. It is also preferable that the entire circuit fits in the 9-V battery compartment. This circuit meets these requirements quite successfully and the design has nonetheless remained fairly simple. In the schematic we can recognise a filter, followed by a voltage regulator and a voltage indicator. D1, which protects the circuit against reverse polarity, is followed by an LC and an RC filter (C3/L1/L2/C1/R1/C2). This filter excludes various disturbances from the motorcycle power system. Moreover, the design with the 78L08 and D3 ensures that the voltage regulator is operating in the linear region. The nominal sys-tem voltage of 14 V can some-times sag to about 12 V when heavy loads such as the lights are switched on.
Although the circuit is obviously suitable for all kinds of applications, we would like to mention that it has been extensively tested on a Yamaha TRX850. These tests show that the converter functions very well and that the interference suppression is excellent. Link
Friday, April 12, 2013
Mobile Cellphone Battery Charger
Charging of the cell phone battery is a big problem while touring as energy provide supply is now not on a standard basis on hand. In case you keep your mobile phone switched on repeatedly, its battery will go flat within to 6 hours, making the mobile phone useless. A absolutely charged battery grow to bes necessary when your distance from the closest relay station increases. Here is an easy costr that replenishes the mobile phone battery inside to hours. Fundamentally, the costr is a current-limited voltage supply. Usually, mobile phone battery packs want three.6-6V DC & one hundred eighty-200mA present for charging. These frequently include NiCd cells, every having one.2V ranking. Current of 100mA is for charging the cell phone battery at a gradual fee. A 12V battery incorporateing eight pen cells provides adequate present (one.8A) to cost the battery related across the output terminals.
![](\"https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjCe95EsRWi5VtJouxTtUCkNjnn9teEhP3TMyVj42YMOWWCeMtuG8xKofjk3Jxz0Zkk61vY_rZ2adXZU27nKf0OMVhynlqJ1X_0b_rWXJKxIvolLzEYQeIyQoMV1Cf7JWWnzGGii6bvZJxu/s1600/cell.jpg\")
Diagram of cellphone costr
The circuit additionally monitors the voltage stage of the battery. It robotically lowers off the charging device when its output terminal voltage will increase above the predetermined voltage level. Timer IC NE555 is used to charge & monitor the voltage stage within the battery. Control voltage pin five of IC1 is supplied with a reference voltage of five.6V with the help of zen-er diode ZD1. Threshold pin 6 is provided with a voltage set via VR1 & trigger pin two is equipped with a voltage set by using VR2. When the discharged mobile phone battery is connected to the circuit, the voltage given to trigger pin two of IC1 is beneath 1/3Vcc & therefore the flip-flop within the IC is switched on to take output pin three excessive.
![](\"https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhBXvbp-En_64kgTOKHBMcK01DMQTmkkJG0Df5JxFw32RciJsSv6t7hIQHvS2p_82cgZBibf7t1elcupGg061U2WxQlFSsuxw6mC9A9w9m7S-0j-Vtg0CWtDEYXn31itEjtyJ5SvC7WAh25/s1600/cell1.jpg\")
When the battery is fully charged, the output terminal voltage will increase the voltage at pin two of IC1 above the trigger level threshold. This switches off the flip-flop & the output goes low to terminate the charging means. Threshold pin 6 of IC1 is referenced at 2/3Vcc set with the help of VR1. Transistor T1 is used to reinforce the charging current. Value of R3 is very important in offering the vital present for charging. With the given price of 39-ohm the charging present is round one hundred eighty mA.
The circuit can be built on a tiny general-purpose PCB. For calibration of cut-off voltage stage, use a variable DC energy source. Connect the output terminals of the circuit to the variable energy supply set at 7V. Fine-tune VR1 within the center place & gradually fine-tune VR2 unless LED1 goes off, indicating low output. LED1 should activate when the voltage of the variable energy supply scale backs under 5V. Enclose the circuit in a tiny plastic case & use suitable connector for connecting to the cellphone battery.
Tuesday, April 9, 2013
Cell Phone Battery Meter Circuit 3 6 Volt
This is a circuit for charger that is 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 set with the 5K adjustable resistor. This is the figure of the circuit;
The programmed voltage of the TL431 is worked out with a voltage divider (10K 5.6K). The adjustment terminal or junction of the two resistors is always 2.5 volts. So, if we use a 10K resistor from the adjustment terminal to ground, the resistor current will be 2.5/10000 = 250uA. This same current flows through the upper resistor (5.6K) and produces a voltage drop of .00025 * 5600 = 1.4 volts. So the shunt regulated output voltage at the cathode of the TL431 will be 2.5 + 1.4, or 3.9 volts.
Working out the LED voltages, there are three 390 ohm resistors in series with another adjustable (5K) resistor at the bottom. Assuming the bottom resistor is set to 2K ohms, the total resistance is 390+390+390+2000 = 3170 ohms. So, the resistor current is the reference voltage (3.9) divided by the total resistance, or about 3.9/ (390 + 390 + 390 + 2000) equals 1.23 mA. This gives us about .00123*2000= 2.46 volts for the bottom LED, and about .00123*390 = .48 volts for each step above the bottom. So, the LEDs should light at steps of 2.46, 2.94, 3.42, and 3.9. A fully charged cell phone battery is about 4.2 volts. You can adjust the 5.6K resistor to set the top voltage higher or lower, and adjust the lower 5K resistor to set the bottom LED for the lowest voltage. But you do need a 6 to 12 volt or greater battery to power the circuit.
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