This circuit found in a 1964 US publication reverses the signal level by providing 9 to 0 V outputs from 0 to 9 V signals. Transistors may be equivalent.
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....