Constant current charging circuit long delay Shown as a long delay using CD4541 constitute constant current charging circuit, suitable for Ni-Cd batteries. When the power is turned on after, CD4541 @ pin output high TWH8778 electronic switch is turned on, the
constant current source formed by the LM317 to charge the battery. After more than ten hours later, CD4541 output goes low. TWH8778 power off, charging is completed.