Found in a 1990s Popular Electronics, this circuit uses two transistors to boost the power of a 741 with audio signals. The power depends on the transistors used, which can be general-purpose types.
The figure shows how to control the blinking of a 5 V blinking LED with an LDR. The LED only...
Suggested by Maxim in documentation from the 90s, this circuit has its response curve given next to...
This circuit is from a 1965 General Electric publication. It uses a thermistor to fire a reed...