Web DiscoverCircuits.com

Electronic Circuits and electronic circuits, electronic schematics plus an extensive resource for hobbyists, inventors and engineers

DiscoverCircuits.com, has 28,000+ electronic circuits, cross-referenced
into 500+ categories.    We have searched the web to help you find quick design ideas.
We make every effort to link to material posted by the designer. 
Please let us if you would like us to link to your design.

HOME Schematics Discover Forum Hobby Corner Dave's Circuits Electronic Resources Book Corner Contact Info
Imagineering Ezine    Discover Solar Energy Dave Johnson &
Associates
My eBay Auctions Faraday Touch Switches

Tester or Instrumentation Circuits, Page 11a
Testers:  #'s     A-B    C     D     E    F-G    H-K    L     M-O    P     Q-R    S    T     U    V-Z

Last Updated on: Friday, March 12, 2010 12:07 PM

Circuits Designed by Dave Johnson, P.E. :
  • RS232 Serial Interface Status Indicator
    I designed this circuit many years ago and have used it several times since.  It uses a single logic IC to indicate the TXD and RXD line activity of a typical RS-232 serial data communications link.  The thresholds are set at plus 3 volts and minus 3 volts.  Two dual color LEDs are used as indicator lights.

Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:
Resistance, DC Current, AC Current, Frequency and Period Measurement Errors in DMMs 5988-5512EN - Aligent Application Note  (app note added 4/08)
Resistor Decade Box - (schematic / circuit added 6/07)
Revolution Meter - Revolution meter by measuring method of strobe synchronization. It can measure up to 100,000 rpm in two ranges.  (added 6/06)
RF Power Meter - Here is a simple set up which will enable them to measure the out put power of their transmitter. All that they require is a good multimeter which has a sensitivety of 20k ohms/4 Watts which is adequate for low power transmitters.  (electronic circuit added 9/04)
RF Power Meter - RF Power Meter for QRPers  (electronic circuit added 03/04/05)

 

RF Power Meter for the QRPer - (electronic design / schematic added 2/05)
RF Probe - Use this probe with any transmitter for tuning. Connect the probe at the output of each stage and tune till maximum DC voltage appear on Digital Voltmeter.  (added 11/05)
Ring oscillator measures cable length - 05/12/94 EDN-Design Ideas:  In Fig 1, an ECL exclusive-NOR gate (F100107) and a length of cable form a simple ring oscillator. The delay from the cable and the gate determine the ring oscillator’s frequency. A 100m cable yields approximately a 600-MHz oscillation frequency. The gate’s second output connects to a frequency counter.  (design idea added 09/05)
RMS Calculations for Energy Meter Applications Using the ADE7756 - AN-578 Analog Devices Application Notes  (app note added 6/06)  The document describes the implementation of an rms signal processing algorithm using the ADE7756 and a Microcontroller (PIC16C63)  from Microchip.
RMS to DC Converter is Accurate and Stable - 09/14/95 EDN-Design Ideas:  Combining the well-known true RMS-to-dc circuit with a simple S/H circuit eliminates offset errors, which increases accuracy and temperature stability. The circuit in Fig 1 uses a low-cost analog multiplier, IC1; an integrator, IC3A, R5, and C1; and an analog inverter,.....(design idea added 11/05)
Rohde & Schwarz FTZ distortion meter schematic - (circuit added 07/07/07)
Rohde & Schwarz LARU Inductance meter schematic - (circuit added 07/07/07)
RS232 Data Bus Status Indicator - This circuit indicates TXD and RXD activity.  The thresholds are set at plus 3 volts and minus 3 volts. (added 12/04) ….(designed by David A. Johnson)
RS232 to TTL converter tests UARTs with a PC - 05/29/08 EDN-Design Ideas:  A simple RS-232-to-TTL converter tests UARTs using a PC's serial port for power.....(design idea added 06/07/08)
RS232C Link Monitors Animal Activity - 11/06/97 EDN-Design Ideas:  (design idea added 6/06)

          Testers Previous Q-R's   
Testers:  #'s     A-B    C     D     E    F-G    H-K    L     M-O    P     Q-R    S    T     U    V-Z
 
HOME Schematics Discover Forum Hobby Corner Dave's Circuits Electronic Resources Book Corner Contact Info

 Linking is welcomed but COPYING any content or graphics to your web site is expressly prohibited.

 About Us   |  Advertise on DiscoverCircuits.com   |   Report Broken Links  |    Link to DiscoverCircuits.com  |    Privacy Policy