Circuits & Schematics - Analogue Design - 10

Numerous and evil are the forces of darkness that conspire to frustrate accurate analog-to-digital conversion of wide-dynamic-range analog signals. Among these gremlins lurk common-mode-voltage noise and signal amplitudes too variable to fully use ...

Figure 1 shows how a Sallen-Key high pass filter (HPF), can be switched on/off using only one extra transistor and resistor. Figure 1. A Sallen-Key HPF filter topology that can be switched on/off using an extra transistor and resistor. This ...

New operational amplifiers optimized for high-performance audio and ultrasound applications combine extremely low total harmonic distortion plus noise (THD+N), 130 dB, with large output voltages on heavy, 600-Ω loads. One would think this ...

Some op amps, such as the AD8041 from Analog Devices and the EL5100 from Intersil, provide a disable pin, which allows you to parallel the outputs of several op amps for video multiplexing. In addition to this multiplexing, you can also use the ...

A signal’s peak is typically measured with a diode. But if the diode is used alone, the input voltage must be much larger than the diode’s turn-on voltage to obtain acceptable accuracy. Since turn-on voltages range from 200 mV in ...

Most inexpensive pushbutton switches, particularly pc-board-mounting and membrane types, have momentary action. Latching types are often larger and relatively expensive, and they frequently are unavailable in the style you'd like to use. You ...

For an inverting amplifier with hysteresis, resistors R A , R B , and R F determine the crossover voltages (Figure 1). Unfortunately, using three resistors to set the upper and lower trip voltages creates a dependence between the two trip voltages: ...

Some amplifier applications require clamping or limiting due to large, sporadic signals appearing at the amplifier input. Clamping these errant signals protects the amplifier and other sensitive downstream circuitry. It also improves overdrive ...

Some of the electrical signals we work with are said to be “floating” with respect to ground. A typical example might be a voltage drop over a shunt resistor in a power supply or a complex biomedical signal, such as an ECG. In such ...

Comparators are great at turning little signals into large digital outputs. In the example described here, a friend wanted to detect the presence of a small 60-Hz AC signal centered on 2.5 V DC. When the AC is absent (beneath the specified ...