Simple Interface Connects Sensor Output To Microcontroller

By Shyam Sunder Tiwari, April 20, 2011

A way to apply the output of certain sensors to a TTL/CMOS-level iput on a microcontroller. Sensor must have an NPN output stage that can support a pullup to its power rail.

Circuit Combines DC High-Voltage Drop Detector, Undervoltage Alarm

By Shyam Sunder Tiwari, December 14, 2010

Description of a circuit to tell if the high-voltage supply in an industrial smokestack precipitator is functioning properly.

Simplify DC High-Voltage Measurements

By Shyam Sunder Tiwari, October 22, 2010

555 Timer Measures Capacitor charge Time to Indirectly Measure High DC Voltages

Measuring Stability In A Logic-Gate-Based Oscillator

By Shyam Sunder Tiwari, March 11, 2010

Simple Light Sensor Circuit Features High Dynamic Range

By Shyam Sunder Tiwari, December 13, 2009

Sensor Signal Converter Outputs Both NPN And PNP Signals

By Shyam Sunder Tiwari, April 23, 2009

A versatile signal-conditioning circuit for use with with programmable logic converters or controllers that can accept only one input polarity.

Low-Power Logic Gate Protects Fluid Sensor From Leakage Current

By Shyam Sunder Tiwari, March 12, 2009

How to make fluid level sensors insensitive to mains-power leakage currents while operating from batteries.

Power Control Circuit Limits On Time To Prevent MOSFET Burnout

By Shyam Sunder Tiwari, February 12, 2009

Design Idea for a simple gated-osciallator circuit to limit MOSFET on-time using an An R-C time to limit On-time pulse period length and generates its own maximum permitted On/Off duty cycle.

Superior JFET Biasing Improves Amplifier Performance

By Shyam Sunder Tiwari, November 17, 2008

An N-channel JFET has a low bias current when its gate is biased negative to the source. However, this requires either that the gate voltage be biased negative with respect to the source voltage or that source voltage be biased positive with resp

Simple Circuit Uses Optical Fiber To Send Relative-Humidity Data

By Shyam Sunder Tiwari, April 01, 2002

The circuit shown in the figure measures relative humidity in air at the low temperatures found in applications like cold storage of food items and greenhouses. Instead of using electrical signal cables that...

Single-Gate VHF Temperature Transmitter Runs On 3.6 V

By Shyam Sunder Tiwari, December 03, 2001

This design idea illustrates what may be the simplest and smallest temperature transmitter in the VHF 50- to 100-MHz range. As seen in the figure, the design employs an ON SEMI single-gate IC (NL27WZ14). The...

Dual Watchdog Timers Improve Embedded Performance

By Shyam Sunder Tiwari, September 18, 2000

This idea describes a new concept that utilizes two watchdog timers instead of the typical single watchdog timer found in most embedded systems. One watchdog is the typical hardware type, which handles recovery from absolute firmware failure. The...

Program Quickly Calculates Transformer Design Parameters

By Shyam Sunder Tiwari, June 12, 2000

Here's a handy C program for the design and verification of transformer characteristics. Design parameters computed include: required core cross-section, primary turns/current, and secondary turns/current.