This light meter circuit was found in 80's Radio Electronics. The circuit uses a milliammeter as an indicator and the sensor is a common LDR. The power supply must be symmetrical.
This interesting comparator circuit was found in an old Motorola documentation. The integrated circuit...
This two-transistor constant current source is from a 1968 documentation. Modern equivalent...
An interesting application that finds applications in industry, especially when fluctuations in...