This Design Idea (DI) offers an alternative solution for an application borrowed from frequent DI contributor R. Jayapal, presented in: “A 0-20 mA source current to 4-20 mA loop current converter” ( Ref. 1 ). It converts a 0/20 mA ...
A 4 to 20 mA loop current is a popular terminology with Instrumentation/Electronics engineers in process industries. Field transmitters like pressure, temperature, flow, etc., give out 4 to 20 mA current signals corresponding to the respective ...
The circuit presented by Cor van Rij ( Ref. 1 ) for characterizing JFETs is a clever solution. Noteworthy is the use of a five-pin test socket wired to accommodate all of the possible JFET pinout arrangements. This idea uses that socket arrangement ...
“Facts are stubborn things” (John Adams, et al). I added two 50-ohm outputs to the schematic of my published voltage-to-frequency converter (VFC) circuit [ 1 ] (Figure 1). Then, I designed a PCB, purchased the (mostly) surface-mount ...
The circuit in Figure 1 converts the input DC voltage into a pulse train. The period of the pulses is proportional to the input voltage with a 50% duty cycle and a nonlinearity error of 0.01%. The maximum conversion time is less than 5 ms. Figure ...
Analog topologies abound for converting current to voltage, voltage to current, voltage to frequency, and frequency to voltage, among other conversions. Figure 1 joins the flock while singing a somewhat different tune. This current, voltage, and ...
Up front: some background. The air-temperature sensor attached to my (home-brew) rain gauge became flaky. Short-term solution: fix it (done). Longer-term goal: improve it (read on). That sensor is a standard Vishay NTC (negative temperature ...
Many recent Design Ideas ( Ref, 1 ) have involved button-pushing to control power. Some may have been more resistant to contact-bounce than others but how can we really check that? This DI describes how some simple circuitry can simulate bouncy ...
Precision-matched capacitor pairs are commercially available items, but only in a limited range of values, working voltage, and dielectrics. Plus, sometimes an extra critical application with extra tight tolerances (or an extra tight budget) can ...
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 ...