To reduce a 12V circuit to 9V, place two resistors in series within the circuit. Find the difference between the two voltages (12V – 9V = 3V) to determine the total amount of resistance needed.

Four practical approaches can be used to minimize voltage drop problems:

1. Increasing the number or size of conductors.
2. Reducing the load current on the circuit.
3. Decreasing conductor length, and.
4. Decreasing conductor temperature.

A resistor has the ability to reduce voltage and current when used in a circuit. The main function of a resistor is to limit current flow. Ohm’s law tells us that an increase in a resistors value will see a decrease in current. To reduce voltage, resistors are set up in a configuration known as ‘voltage divider’.

1. Simple voltage dropping isn’t efficient, and efficient voltage dropping isn’t simple.
2. The proper solution is a 24 to 12 V switching regulator, at the end of the wire, as you have surmised.
3. You could wire up a relay on a timer to swap between the batteries every five minutes or so.

The simplest way is a 12 v battery and a resistor from its positive terminal to the 19 v positive supply. Connect the load accross the battery. And the other terminal of the 19 v to the other terminal of the battery… .

PLace two resistors in series with the 2nd resistor value (5/7) of the first resistor value. Place the resistors between 12v and ground and then you will get 5v at the point between them. This is a very crude way of doing it. It is unregulated so the voltage out will be dependent of voltage in.

To convert 5 v to 3.7 v at fixed load ,we just have to add a fixed series resistor. 5 to 3.7 that means our series resistor have to create 1.3 v drop across it. For load 0.5A , R= 2.6Ohms and power rating is 0.65W. Idea of using zener diode is good with small series resistor.

As we know, in most cases, a 5V charger can be used for USB of computers and mobile phones. The charging cut-off voltage of 3.7V battery is 4.2V and the discharge cut-off voltage is 3.0V. Therefore, when the open-circuit voltage of the battery is lower than 3.6V, it should be able to charge.

Ohm’s law states that the electrical current (I) flowing in an circuit is proportional to the voltage (V) and inversely proportional to the resistance (R). Similarly, increasing the resistance of the circuit will lower the current flow if the voltage is not changed.

The current in a circuit is directly proportional to the electric potential difference impressed across the circuit and inversely proportional to the resistance of the circuit. Reducing the current can be done by reducing the voltage (choice A) or by increasing the resistance (choice D). 2.

A process whereby the rate of charging is reduced as the battery approaches its fully charged state.

Trickle charging means charging a fully charged battery at a rate equal to its self-discharge rate, thus enabling the battery to remain at its fully charged level; this state occurs almost exclusively when the battery is not loaded, as trickle charging will not keep a battery charged if current is being drawn by a load …

Constant-current charging simply means that the charger supplies a relatively uniform current, regardless of the battery state of charge or temperature. Constant-current charging helps eliminate imbalances of cells and batteries connected in series.

During constant voltage or taper charging, the battery’s current acceptance decreases as voltage and state of charge increase. The battery is fully charged once the current stabilizes at a low level for a few hours.