Testers or Instruments Electronic Circuits, Page 4

Tester or Instrumentation Circuits, Page 28
Testers: #'s A-B C D E F-G H-K L M-O P Q-R S T V-Z
Last Updated on: Friday, March 12, 2010 12:07 PM

Circuits Designed by Dave Johnson, P.E. :

TEMPERATURE SENSOR WITH 4 TO 20mA CURRENT LOOP
I designed a circuit similar to this one years ago to accurately measure the air temperature inside a building 1000s of feet from a control room. The circuit uses the very robust current loop method. It uses a highly accurate semiconductor temperature sensor and an equally accurate voltage reference. The circuit includes a diode bridge, so it is polarity independent. By using the component values indicated, the circuit should not require calibration. It has a range from –40F to +120F and an accuracy of plus or minus one degree F.

Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

Three Channel Spectrum Analyzer - ….(circuit design added 03/08)

Three Level Audio Power Indicator - Battery-operated3 LED display that connect it to loudspeaker output (added 04/02)

Three-Level Audio Power Indicator - Battery-operated 3 LED display. Simply connect it to loudspeaker output. (electronic circuit added 06/07/08)

Time Domain Reflectometer - (circuit / schematic added 2/03)

Tiny pH Meter - This tiny pH-meter is very tiny: 11cm2 including the PSU circuit! I built it for the College Saint Pierre a few years ago. It is based on a circuit developped at the Facultes Notre-Dame de la Paix, Namur, Belgium. I modified several components to allow a smaller power supply...(schematic added 6/07)

Tiny twisted pair transmission line solves test fixture woes - 12/16/05 EDN-Design Ideas: Commonly available wire fits in tight spots.....(design idea added 9/08)

Trace Voltage Current curves on your PC - 10/11/01 EDN-Design Ideas: Some years ago, one of the fundamental electronic instruments was the laboratory curve tracer. A CRT display would sweep out terminal behavior (current versus voltage)from which you could derive mathematical models. Classic presentations of diodes, transistors, and other devices enlightened designers about linear and nonlinear operation.....(design idea added 1/05)

Track multisite temperatures on your PC - 04/18/02 EDN-Design Ideas: The low-cost circuit in Figure 1 allows you to track four remote temperatures with thermistor sensors through the parallel port on your PC. This four-zone thermometer instrument has a temperature range of -40 to +90 C and a resolution of better than 1 C. You can calibrate its accuracy to within 1 C over a 0 to 50 C span and within 3 C over a -40 to +90.....(design idea added 1/05)

Transformerless Power Supply (Aaron Cake) - (electronic design added 08/08)

Transformerless Power Supply (jose pino) - Simple, low cost and easy to build power supply. Ideal for applications that doesn't requiere too much power. (5/28/2006)

Transformerless Power Supply (Len Galasso) - This power supply uses the reactance of a non-polarized capacitor at 60hz to step-down the voltage from the normal 117VAC level to about 20 volts or so, which is rectified by the diode….(circuit design added 7/06)

Transformerless Power Supply (Ron J) - This circuit will supply up to about 20ma at 12 volts. It uses capacitive reactance instead of resistance, so it doesn't generate very much heat. The circuit was desigusing an optically-isolated triac.... (added 6/03)

Transient test correctly models nonlinear parts - 11/23/94 EDN-Design Ideas: (design idea added 2/06)

Transistor junction monitors remote temperature - 06/22/00 EDN-Design Ideas: (design idea added 2/06)

Transistor quickly wakes sleeping LDO - 09/01/98 EDN-Design Ideas: Portable systems, such as telephone handsets, make extensive use of low-dropout (LDO)regulators. These components provide noise-sensitive parts with a stable power-supply line. When a telephone enters standby mode, most of the circuits go to sleep by disabling the LDO's outputs. Operating.....(design idea added 110/05)

Transistor Spot Checker - (circuit added 07/07/07)

Transistor Tester - ….(circuit design added 08/08)

Transistor tester and signal injector - There have been a lot of transistor tester circuits in recent electronics magazines, but this one is different. It has more features and includes a signal injector so you can test audio sections of radios and the front end of FM transmitters etc....(electronic design added 02/03/04)

Transistor tester fits into your pocket - 12/20/01 EDN-Design Ideas: It can be helpful to rapidly and easily determine the polarity (npn or pnp)and function of a transistor. The pocket-transistor tester in Figure 1 is ideal for quickly testing without regard to such parameters as gain and frequency response. You connect the transistor, or device under test, between the collectors, T, of an astable multivibrator.....(design idea added 1/05)

Transistor Trio Makes Vector Anemometer - 09/01/97 EDN-Design Ideas: (design idea added 3/03)

Transistor & FVCs Make Linear Anemometer - 09/26/96 EDN-Design Ideas: The basic operation of this front-end sensor is identical to that of the earlier circuit. Q1 is the self-heated airflow sensor; Q2 senses ambient temperature. Zero-adjust resistor R2 sets the zero-airflow quiescen.....(design idea added 11/05)

Transition counter gauges thermal stability - 01/04/96 EDN-Design Ideas: (design idea added 2/06)

Transmission Line Characteristics - National Semiconductor Application Note (app note added 2/06)

Transmission Line Enclosure Speakers - Built for my Ambisonic surround rig, and an interesting project. But don't do this unless you're clinically insane; Buy them instead. (electronic circuit added : 08/08/08)

Transmission Line Terminations - ...(spice design added 02/09)

Transmission line tests 1 kW Deviceusing only 100W - 02/20/03 EDN-Design Ideas: A 13.56-MHz, ISM (industrial, scientific, and medical)-band RF-measurement device had the test requirement of a 50-hour, 1-kW burn-in. The device under test needed to be simultaneously stressed at an RF potential and RF current equivalent to 1 kW, but the only spare RF source at hand was a 100W RF generator.....(design idea added 02/05)

Transmission lines simulate digital filters in PSpice - 04/17/08 EDN-Design Ideas: You can simulate digital filters in PSpice by using transmission lines as delay elements.....(design idea added 09/08)

Transmitter Accurately Transfers Voltage Input - 05/15/03 EDN-Design Ideas: When you connect remote sensors to a central process controller, a simple, robust, and commonly used interface is the 4to 20-mA loop. The advantages of this current loop include the simplicity of just two twisted wires that share both power and signal, the loop's high noise immunity in harsh environments,.....(design idea added 9/03)

Triac Test - These two testing procedures are for use with a digital multimeter in the Ohm's test-range. Testing procedure was actually designed for testing inside micro-waves (magnetrons), but should be no difference in any other circuit. Test inor out circuit. (added 2/06)

Triac tester allows for manual or automatic operation - 08/20/09 EDN-Design Ideas: Build a simple triac tester with a switch or an automated tester with a microcontroller.....(design idea added 08/09)

True RMS Detector - National Semiconductor Application Notes,28-Jun-1996 / (app note added 6/02)

TTL Pulse Reading Logic Probe - This circuit uses LEDs to display logic states for high, low, rising pulse, and falling pulse, it is generally useful for debugging logic circuitry. (electronic design added 6/07)

TV Oscilloscope Adaptor - This is an adapter attached to a TV set. This machine changes a TV to a Oscilloscope. See the photo! This photo indicates a sine wave 50mV 120Hz. See the circuit! Free oscillater makes an 15kHz pulse signal (A). This signal is amplified by an buffer AMP. On the other hand , an amplifier makes 300 times of input signal. And it is shifted to 6V center. A comparater ….(electronic schematic added 11/08)

TV Oscilloscope Adaptor #2 - Low frequency TV Oscilloscope (circuit added 8/06)

Two Sensors Measure Three Line Currents - 09/01/95 EDN-Design Ideas:.....(design idea added 3/03)

Two Simple Crystal Test Circuits - ….(circuit design added 03/08)

Two Tone Audio Oscillator use for SSB Tests - (electronic design / schematic added 2/05)

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