High Current Charger with Cut Off. Utility Gadgets.7

Many of my readers require a High current battery charger with battery protection facility. So I am posting this circuit for charging 12 volt Lead Acid battery using Mains power. The same circuit can be connected to Solar panel also. The circuit has features like
1. High current charging
2. Voltage regulation
3. Current regulation
4. Full charge cut off
5. Battery protection
6. LED status indicators

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Car Battery Monitor. Beginner’s Trial 14

Monitor your Car battery or Inverter battery with this simple circuit. It always follows the terminal voltage of the battery and gives corresponding LED indications. A 12 volt Lead-Acid battery attains 13.85 volts in full charged condition and Inverter Tubular battery 14.85 volts. So it is necessary to have an idea about the charge status of the battery. If the battery discharges below 10 volts, it needs immediate charging to prevent the deep discharge. The circuit gives three LED indications. If the terminal voltage of the battery rises above 13.5 volts, Red LED lights. If the voltage drops below 10 volts, Green LED lights. If the voltage is normal around 12 volts, both the LEDs remain off.

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Familiarize Electronic Components Part XII – OpAmps

Operational Amplifier or OpAmp is a DC coupled amplifier with differential inputs and usually with a single output. An OpAmp can deliver an output voltage hundreds or thousand times greater than the voltage difference between its inputs. OpAmps may be single, dual, quad etc. In single OpAmps only one OpAmp is present while in dual type two OpAmps with separate inputs and outputs are present. In quad OpAmp, four OpAmps are present in the single package. Some of the OpAmps like CA3130, CA3140, TL0 71, LM311 etc have excellent performance with very low input current and voltage.

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Tristate Battery Level Indicator

Here is a simple but useful battery level indicator to monitor the battery terminal voltage.Efficiency of the battery reflects in its terminal voltage. A good Lead Acid battery will show 13.8 volts in the fully charged state and if it is below 10 volts, the battery needs immediate charging. If the battery voltage goes above 14 volts, it is in the overcharged condition. This circuit uses a two lead bicolour LED to indicate three battery levels. If the voltage is below 10 volts, the Green part of the LED lights and if the voltage is above 14 volts, the Red part lights. If the battery voltage is between 10 to 14  volts LED remains off.

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Excellent Op Amps

CA 3130 and CA 3140 are excellent Operational Amplifiers for Signal detection circuits. The most important characteristics of these Op Amps are low input current requirements and the zero output in the off state. Some of the general purpose Op Amps will not give a zero output in the off state which will affect the working of the remaining circuitry. More over the input current requirement is also high in most Op Amps so that these devices cannot be used in circuits based on Photo diodes and Infrared sensors.
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