Circuits & Schematics - 7

The popular I 2 C communication standard manages to perform flexible serial I/O with just a super simple two pin bus: SCL and SDA. It accomplishes this trick with bidirectional timing and data flow. Bidirectional flow is good at saving pins but due ...

Several years ago we were developing a clamp-on photometer, a hand-held instrument that could be clamped onto a communications optical fiber to indicate the presence of light, its direction of travel, and the presence of combinations of ...

When a system's specifications call for a lowpass filter with a steep frequency-cutoff characteristic, an engineer can opt for a “brick-wall”- filter design that features a sharp transition band. For example, in an FM ...

The basis for this Design Idea is a circuit that uses three resistors and a microcontroller-I/O pin to work as input high impedance or output to independently drive two LEDs ( Reference 1 ). The idea sounded good for this design, mainly because of ...

A typical switched-capacitor charge pump requires no inductors, is easy to design, and can double a positive voltage or convert a positive voltage to an equivalent negative voltage. However, in some applications, only a positive supply is ...

Testing the system Testing was done at various sunlight intensities. For any given sunlight intensity, V PV , I PV , V M , I M , etc., are measured. Figure 5 shows the variation of PV power (P PVON ), converter power (P M ), and total power (P TOT ...

The PV-pushback-effect with solar panels can control backup power and provide constant light output. Solar day lamps (SDLs) are made by simply connecting an LED array to a solar photovoltaic (PV) panel. SDLs represent a highly cost-effective way of ...

Junction field-effect transistors (JFETs) usually require some reverse bias voltage to be applied to a gate terminal. In HF and UHF applications, this bias is often provided using the voltage across the source resistor R S (Figure 1). Figure 1. ...

While an internal, rechargeable lithium battery is usually the best solution for portable kit nowadays, there are still times when using replaceable cells with an external power option, probably from a USB source, is more appropriate. This DI shows ...

Self-heated transistors used as thermal air flow sensors are a particular (obsessive?) interest of mine, and over the years I must have designed dozens of variations on this theme. Figure 1 illustrates one such topology seen here (Reference 1) ...