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 circuit for old photo enlargers was found in a 1970s RCA manual. The components are from the...
This CMOS oscillator circuit generates signals up to a few megahertz, depending on the capacitor value....
This circuit was found in a 1977 Radio Handbook. The ports used are CMOS like 4001 and the...