The recent EDN article of Bruce Trump () on the input impedance of an op-amp circuit took into account the single-pole roll-off of its loop gain. He showed with a simple derivation how the equivalent ...

In the early days, PNP bipolar transistors were common, but the bulk of circuits you see today use NPN transistors. As [Aaron Danner] points out, many people think PNP transistors are “backward” but ...

The circuit is a sensitive preamplifier using an N-Channel FET and a PNP transistor. This combination gives high input impedance and low output impedance with stabilized gain. Any general purpose PNP ...

Manufacturing companies, particularly those that mass-produce electronic circuits, work pretty much around bipolar junction transistors, like PNP and NPN. However, choosing between these two BJTs can ...