The presented circuit uses a PNP transistor, which can be the BC558. Observe the polarity of the supply. The circuit is suggested by Texas Instruments opto-electronic documentation.
This simple circuit is designed to charger AA or AAA Nicad batteries. Current can be changed...
The circuit shown in the figure is suggested by Texas Instruments in its Linear Circuits...
A touch of a sensor triggers this minute for a time determined by R4 and C3. Times can be between a...