This step of two transistors has a high input impedance due to the use of FET. We can use BF245 for this function and the bipolar can be BC548. The circuit is from an 1975 American documentation.
This circuit was found in a 1977 documentation. With it we have the direct indication, through LEDs...
In the figure we have the CMOS logic test circuit developed with the 4049. The circuit activates three...
This headlight reminder for your car was found in the May 1970 issue of Radio Electronics...