Circuits & Schematics - 17

When coach cars of long-range trains comprised compartments for six to eight passengers, the passengers could choose either “white” or deep blue light. The blue light helped passengers sleep, even when they were not in full darkness. ...

Recently available visible lasers can be operated from 1.5 V supplies, given appropriate drive circuits. Because these lasers are exceptionally sensitive to overdrive, power to the laser must be carefully controlled lest it be damaged. ...

When you design a transformer for any power converter, you face several compromises. You must trade off core size against the number of primary turns and flux density. Another trade-off is the number of turns and winding resistance versus the ...

Figure 1 is a micropower voltage-to-frequency converter. A 0 V to 5 V input produces a 0 kHz to 10 kHz output with a linearity of 0.05%. Gain drift is 80 ppm/ C. Maximum current consumption is only 90 µA, almost 30 times lower than currently ...

Designers often choose a super-regenerative receiver despite its frequency instability and poor selectivity for battery-powered, short-range, wireless applications in which power consumption is a major issue. Examples include remote-keyless-access ...

Most circuits are referenced to ground, where relatively low-voltage components can monitor and control the low side of a load but not the high side. For example, nearly any low-voltage rail-to-rail-input op amp can detect a voltage increase ...

Analog circuits for long-term testing of passive components, such as 0.1%-tolerant resistors or high-intensity white LEDs, often require a constant current. Using two op amps and a voltage reference, you can develop a circuit that provides a ...

Linear regulator ICs are commonly used in variable power supplies. Common types such as the 317 can be adjusted as low as 1.25 V in single-supply applications. At low output voltages power losses in these regulators can be a problem. For example, ...

A typical SCR (silicon-controlled rectifier) requires a trigger current, which causes the SCR structure to latch on. Once the device latches, the current through the SCR is solely a function of external component values. The SCR has no inherent ...

Adding a manual reset to a design usually involves designing in a new part with a manual-reset input. But, by adding a couple of low-value resistors, a standard three-pin-reset supervisor can work in most applications. The circuit in Figure 1 ...