This circuit is from a 90s Popular Electronics. It consists of a power source for bass amplifiers of common types at the time that used symmetrical power and separating filters.
In the figure we have 3 oscillators with logic gates that can be triggered by external logic...
This circuit uses a Motorola component from the 90's and is suitable for the diode-transistor...
This circuit activates an incandescent lamp (or LEDs) when the light stops hitting the sensor, which...