We began with a bit of revision of resistors used as potential dividers, and of how the impedance of a capacitor depends on frequency.
Thus armed, we were able to discuss the basics of Operational Amplifiers, and the importance of negative feedback for controlling the gain of an amplifier. We considered the merits of single and dual rail power supplies. We looked at the concept of altering waveforms by introducing non-linear elements into the feedback loop.
No doubt we will be re-visiting the subject of Op-Amps in the future, as they are used in many types of circuit.
The session finished with a quick look at a problem bought in by one of our members - a control unit for an immersion heater connected to solar panels. This lead us to discuss a device called a Triac, and how to test one. it made us think that a session on solar panels might be idea sometime.