LR03 alkaline battery

　　Judgment of positive and negative poles in LR03 alkaline battery circuit diagram

　　Various batteries are generally marked with positive and negative poles. If the positive and negative pole markings of the LR03 alkaline battery are unclear, you can use the DC voltage range of a digital multimeter to determine the positive and negative poles of the LR03 alkaline battery. We know that when measuring DC voltage with a digital multimeter, there is no need to consider the polarity of the DC voltage. If the red and black test leads are connected to the positive and negative poles of the LR03 alkaline battery, the voltage value displayed at this time is positive; if the red test lead is connected to the negative pole of the LR03 alkaline battery, the black test lead Connect the positive terminal of the LR03 alkaline battery. At this time, there is a "-" sign in front of the voltage value displayed by the multimeter, so use a digital multimeter to measure the LR03 alkaline battery voltage. If there is no "-" sign in front of the displayed voltage value, the electrode the red test pen touches is the LR03 alkaline battery's positive electrode. If the questioner does not have a digital multimeter, you can also use a light-emitting diode to determine the positive and negative poles of the LR03 alkaline battery. The circuit is shown in the figure below.

　　Simple LR03 alkaline battery polarity identification circuit.

　　The LED in the picture is a high-brightness red light-emitting diode, R is the current limiting resistor, and 1N4148 is the protection diode. This circuit can identify the positive and negative poles of 2~48V batteries. When the LR03 alkaline battery voltage is below 12V, the 1N4148 diode can be omitted. When in use, connect ends a and b to the two electrodes of the LR03 alkaline battery respectively. If the light-emitting diode lights up at this time, the electrode in contact with end a is the positive electrode of the LR03 alkaline battery. If the light-emitting diode does not light up during detection, the electrode in contact with end a The electrode is the negative pole of the LR03 alkaline battery.

　　NiMH LR03 alkaline battery pack.

　　When judging the positive and negative poles of a 12-48V LR03 alkaline battery, you need to add a 1N4148 diode to prevent the light-emitting diode from being reversely broken down. Because the withstand voltage of high-brightness light-emitting diodes is low, when measuring batteries above 20V, if the light-emitting diode pole If the polarity is reversed and there is no protection diode, the light-emitting diode may be easily damaged by breakdown. In addition, when judging the polarity of a 36-48V LR03 alkaline battery, the resistance of the current-limiting resistor R should also be increased, and a 10KΩ/½W resistor can be used.

　　Homemade simple LR03 alkaline battery discharge meter circuit diagram

　　Using the brushed controller of an electric vehicle (48V×8A≈400W), I made a homemade LR03 alkaline battery discharge meter, as shown in Figure 1. When the LR03 alkaline battery voltage drops to 42V, the brush controller will no longer output and will sound an alarm. 48V electronic horn for electric vehicles. The time measurement system directly uses electronic clocks on the market to measure time. After the electronic clock is powered on, it starts timing from "0.00". When the speaker sounds an alarm, the time displayed by the electronic clock is the LR03 alkaline battery discharge time. Multiplying this time by the discharge current is the actual capacity of the LR03 alkaline battery group.

　　In actual use, a red clip is welded to the positive end of the discharge meter to connect to the positive pole of the LR03 alkaline battery pack, and a black clip is welded to the negative end to connect to the negative pole of the LR03 alkaline battery pack. At this time, the electronic clock starts timing, and at the same time a loud alarm sounds from the speaker. Press it quickly. ANI (button switch without self-locking), the horn will no longer sound, and the ammeter should indicate discharge current. When the voltage of the LR03 alkaline battery pack drops to 42V, the controller will stop output, relay K loses power, normally open contacts K1 and K2 are disconnected and will no longer continue to discharge, normally closed contacts K1 and K3 are closed, and a loud sound is emitted from the speaker. The alarm sounds to indicate that discharge is complete. At this time, write down the time displayed by the electronic clock. This time is the discharge time of the LR03 alkaline battery pack. Then multiply this time by the discharge current to estimate the actual capacity of the LR03 alkaline battery pack. This method is convenient and practical, and interested colleagues may wish to give it a try.

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