This low noise preamplifier has a gain of 19 dB in the 30 MHz band. The circuit is from the 80s. Transistors are from the era, and equivalents can be used. The circuit consumption is 13 mA.
The inverter circuit shown in the figure can be used to power a fluorescent lamp in an emergency...
This circuit was found in 80's Popular Electronics. The circuit uses an infrared-sensitive phototransistor...
Found in documentation from the 1980s, this circuit generates signals that can reach a few...