NiCd battery chargers

190NiCd battery chargers Quite arguably, Nickel Cadmium (NiCd) batteries are frequently used as replacements for disposable types of battery; this is possible because they can be inserted readily in the existing battery compartment and supply the same voltage as dispos- able batteries. The fact that one need not go out to purchase (relatively ex- pensive) batteries puts the recharge- able cells in an advantageous pos- ition. However, one drawback of the use of rechargeable batteries is the need to remove them from the equipment any time their charge is exhausted. It would, therefore, be convenient to leave them where they are, i.e. in the battery compartment, as they receive the charge current. Two circuits are suggested for the in- corporation in existing battery- operated equipment. Figure 1 shows the absolute minimum in the form of a simple current source. The refer- ence voltage is obtained from the for- ward drop across LED Di (about 1.5 V for a red LED). R2 fixes the cur- ...