The digital stompbox specialist serve up an analogue solution for amp-free rigs, with a super-tough active DI box offering ...

So, even bipolar amplifiers with “low” output impedance can have imperfect gain and linearity due to thermal feedback from the output transistors to the input stages.

It’s common practice to series-terminatean op amp to match theimpedance of the load. This practicecauses a 3-dB loss of output power in thetermination resistance, however (Figure1 ). Newer op amps ...

Output-impedance measurements The simplest solution is to measure the output impedance of the op amp, in-circuit, using a 1-port reflection measurement in a VNA (vector-network analyzer).

The higher the output resistance of the source, the greater the magnitude of the response deviations. The attenuation can be approximated given the source resistance and impedance vs. frequency: where ...

The output impedance of an emitter follower is significantly lower than that of a common emitter amplifier, allowing it to drive much more demanding loads.

Into high-impedance loads you can expect the maximum output from the headphone amp to be about 7.5VRMS. Clearly there’s never going to be a shortage of power even with high-impedance, low-sensitivity ...

The input impedance matching is important. Due to the bias currentfrom the positive and negative input port, input impedance mismatchleads to input offset voltage. The input offset voltage will ...

Output impedance is key to analog designs and Bob gives his usual insights on the topic.