This circuit is from old documentation, but it can be implemented with more modern equivalent components. The transistor can be the TIP31 with a heatsink and the 1N4002 diodes.
This high-gain digital amplifier uses general-purpose transistors. The supply voltage is logic...
We found this circuit in the March 1993 issue of Electronis Now magazine. The circuit uses common...
Using an LDR as a sensor and an operational amplifier this circuit was found in the Encyclopedia of...