There are many types of battery chargers on the market: rechargeable alkaline battery chargers, nickel-metal hydride battery chargers, and nickel-cadmium battery chargers. When buying a battery charger, I suggest you buy a multi-function battery charger which can reduce some expenses.
Here is a circuit schematic diagram of the battery charger probe that can be tested by using the probe to prevent battery damage, whether the charger starts charging or improperly connected.
This battery charger probe prevents damage to the battery or allows you to test it yourself, whether the charger starts charging or improperly connected. By using the probe, the cable clamp is connected to the battery positive level for the first time, then the test board touches the negative pole of the battery.