This amplifier with two FETs in direct coupling (cascode) was found in a 90s Popular Electronics. The MOSFET can be of almost any type like the MPF102.
We can implement this filter with more modern equivalent operational amplifiers, since the LM110 is...
This stethoscope or amplifier for hearing aid using a crystal headset and microphone was found in a...
The normal use of a 4520 as a divide-by-16 counter is shown in Figure bellow. In the normal...