Polarity protection

In many cases, the battery or batteries in electronic equipment may be inserted with incorrect polarity. It is, therefore, advisable to use polarity protection such as shown in the diagrams. It should be noted that although a Schottky diode may be used, this causes a voltage drop of a few hundred millivolts, which in the case of a 3 V or 1.5 V battery supply is too much. The protection in the diagrams does not cause any reduction in the supply voltage.