Positive feedback is used in oscillators to maintain running or oscillating. An oscillator is basically an amplifier which has a feedback path from the output back to the input. This allows a portion ...

A current-feedback amplifier is a well-known component with many uses. Its basic block diagram shows that its input stage is a voltage follower—in practice, a symmetrical emitter follower (Figure 1).

Fig 1. This Pierce-series resonant oscillator can reliably start at supply voltages as low as 2.4 V. It also draws very low current, ensuring long battery life. Fig 2. An oscilloscope photo shows the ...

Phase-locked-loop (PLL) frequency synthesizers are signal sources often employed in many types of electronic equipment. They show up as clock sources in high-frequency instruments and as local ...