I recently published a simple design ( Ref. 1 ) for a platinum resistance detector (PRTD) 4 to 20 mA transmitter circuit, illustrated in Figure 1. Figure 1. The PRTD 4 to 20 mA loop transmitter with constant current PRTD excitation that relies on ...
Accurate, inexpensive, and mature platinum resistance temperature detectors (PRTDs) with an operating range extending from the cryogenic to the incendiary are a gold (no! platinum! ) standard for temperature measurement. Similarly, the 4 to 20 mA ...
In the early days of personal computers, incorporation of one or two (or more) RS-232 serial ports as general purpose I/O adaptors was common practice. Recently, this “vintage” standard has been largely replaced (after all, it is 64 ...
A high-side current-sense amplifier, IC 1 , offers a simple method of combining low-speed clocks or other signals with dc power in cables between subsystems (Figure 1). Designed for monitoring charge and discharge current in secondary batteries, IC ...
The 0- to 20-mA current loop is a reliable means of data communication in industrial applications. These circuits use a precision shunt in the receiver to convert the current signal into a voltage signal. Accidentally connecting the precision ...
Systems using line receivers for differential input signals require an adequate self-test capability. Using an LM339 (a quad differential comparator), you can provide this capability by constructing the configuration shown in the Figure 1. ...
It is advantageous to know if there is a valid signal on a differential signal bus. This Design Idea detects differential data transmission and reports a loss of signal (LOS) to a microcontroller or other monitoring device. The circuit of Figure 1 ...
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 ...
I 2 C is a popular bidirectional serial communications bus having a clock and a data line. Both line’s drivers consist of an open drain ground-referenced N-channel MOSFET with a pullup resistor connected to a supply ranging from 1.8 V to 5 V. ...
It’s common for I 2 C systems to have both standard and fast devices on the same bus. For I 2 C systems, the speed and power consumption both depend on the values of pullup resistors: the values of them should be low enough to secure the fast ...