Found in an English publication in 1969, this circuit has a 600 kHz pass band. Ferranti's transistors support modern equivalents.
This circuit uses only passive components calculated for the desired frequency. We found it in an...
This fourth-order circuit was found on an 80's Radio Electronics. The power supply must be...
This simple circuit controls the brightness of an LED from LDRs, NTCs, PTCs or other resistive sensors....