An uncomplicated yet highly practical charger, initially introduced years ago (originally spotted on a birdcage), is commonly referred to as a spider charge or insect charge 🙂 Despite its low power output and extended charging duration, its unique mechanical design accommodates and charges various devices, including mobile phones. The charging circuit is constructed using the LM358 operational amplifier.
The high-resolution scheme of the same unit and a similar scheme:
To initiate the charging process, activate the battery by releasing the clamps on the device.
Position the clamps securely onto the positive (+) and negative (-) terminals of the battery.
Next, press the “TEST” button (labeled as K1 TE Button on the schematic).
Upon connecting the adapter to the socket, the “PW” indicator will illuminate steadily in red, and the “CH” indicator will begin to flash in green.
This indicates that the battery charging has commenced.
If the “CH” indicator fails to light up, it indicates a polarity mismatch with the battery. To rectify this, press the “CO” button to automatically adjust the charger’s polarity.
Once the charging process is complete and the battery is fully charged, the “PW” indicator will flash brightly in red.
The LM158 series comprises two separate operational amplifiers with high gain and internal frequency compensation. These amplifiers are specifically engineered to function efficiently using a single power supply across a broad voltage range. They can also operate with split power supplies if needed, and their low current consumption remains consistent regardless of the power supply voltage magnitude.