Battery Circuit DiagramsVoltage Regulators Circuit Diagrams

Voltage Regulator For Cars Schematic Circuit Diagram

Mechanical vs. Electronic Battery Charging Voltage Control in Older Cars

In traditional automobiles, the control of battery charging voltage relies on mechanical mechanisms. A regulator, comprising a relay that toggles the stator windings of the alternator, is used. However, this setup is susceptible to breakdowns, imprecise regulation, and sensitivity to fluctuations in load. An electronic alternative, depicted here, offers notable advantages. It eliminates moving parts and delivers highly accurate regulation. Additionally, the voltage is gauged directly at the battery terminals, ensuring the measurement excludes losses incurred in the wiring.

The Functionality of the Electronic Regulator: Precision in Voltage Control

The Electronic Regulator (IC) serves as a device that continuously compares the battery voltage with a predetermined reference potential. This comparison is managed by a comparator, which in turn controls a power transistor responsible for modulating the excitation of the alternator. This electronic approach guarantees more stable and accurate regulation of the charging process, enhancing the overall efficiency and reliability of the vehicle’s electrical system.

Voltage regulator for cars Schematic diagram

Establishing Connections and Voltage Regulation: Terminal Configuration

Terminal Z1 is linked to the battery’s positive terminal; Z2 connects to the ignition switch; and Z3 interfaces with the stator winding of the alternator. The battery voltage undergoes a reduction to approximately 5 V through the potential divider R1-R2-P1. This diminished voltage is then directed to the non-inverting input of Schmitt trigger IC1. Meanwhile, the inverting input of IC1 maintains a constant reference potential of 5 V. A function overseen by regulator IC2. Power transistor T1 controls the output of IC1 as well as transistors T2 and T3. Diode D2 operates as an indicator, while D1 functions as a free-wheeling diode. Capacitor C6 plays a crucial role by mitigating the pulse generated when T1 is activated. Significantly reducing harmonics and suppressing interference on medium-wave radios.

Regulator Calibration and Construction: Precision Adjustment and Encasing

The regulator’s calibration involves the connection of a 12 V lamp or a 15 S2 or 10 W resistor between Z3 and the ground. Simultaneously, a variable power supply and multimeter, set to 15 V, are connected between Z1 and the ground. Adjustments are made by setting the power supply output to 14.3 V and fine-tuning P1 until the lamp extinguishes. To confirm the regulator’s effectiveness, gradually reduce the power supply output; the lamp should reiluminate at 13.9 V.

For optimal performance and heat dissipation, it is advisable to construct the regulator within a compact aluminum case, which also functions as a heat sink for T1. To ensure durability and protection against environmental factors, the case can be rendered watertight using a suitable silicone paste that hardens upon application.

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