A few handy tools for electrical

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This page contains several tools I have found useful over the years in developing various projects.  Like modeling, some are purchased “ready-to-run”, some are like “kit-bashing”, while others are more like “scratch building.”   Please send me a line if you find anything useful or have any questions.    E-MAIL HERE

       

    

   

 

       

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Almost any project of any size is easier when prototyping with breadboards to test new circuits.  These come in many versions and are readily available.  This breadboard has interlocking lugs along the side such that any number of breadboards can be joined together for prototyping larger circuits.

 

Sometimes the breadboard is nested or mounted on a base like this electronics project trainer.  It has circuitry such as a power supply, switches, and some on some sort of display.  This old standby contains a power supply with on/off switch, a bread board, a square wave generator, four LEDs, Two switches and of course a bread-boarding area.  Unfortunately, it is no longer available but other devices like it are.  Note that this type of hole pattern is available both with solderless connections and separately on a PC board where the connections must be soldered.  There are also a number of prototyping boards for any need.

PT_265

PT_212

Many circuits can be broken down into common building blocks.  One way to avoid this repetitive task is to build small building blocks to go with the prototyping board.  The small power supply in the upper left has a LED to show when power is on and provides five volts DC at about 1/10 amp. 

 

The module at the upper right is simply a beeper that is turned on or off by either the switch or a signal. 

 

The small transformer is typical of many small projects and the fuse is for larger circuits that may need protection.

Some projects may require a set of push buttons, switches or other controls.  This shows a more complex sub-circuit used to develop a sound system and contains a power supply for the entire project.  The controls represent a simulated computer interface.  This board will not be part of the finished project.  

    

 

 

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MULTI-METERS ARE A MUST FOR DEVELOPING AND TESTING PROJECTS.  TYPE a is a rugged, reasonable priced meter from DigiKey.

 

A good digital multimeter is generally more rugged and mobile.  

Meters are an important tool and I use several.  Most meters  will measure resistance, voltage (AC and DC) and usually current (Also AC and DC).  There should be fuses to protect the meter against excessive current.  This model stores spares inside for convenience.   This model also measures capacitance while others can also measure inductance as well as the integrity of diodes and transistors.

 

Old fashioned Analoge meter

    

An old-fashioned analog multi-meter can “see” fluctuations and spikes that a digital meter ignores.  It also is easier to interpret any fluctuating measurements.  This 40-year-old meter still works and sees occasional use.  It can measure house current up to 30 amps and is more accurate then most smaller meters.

 

 

 

 

This simple but extremely rugged meter was part of a build-it-yourself color television kit.  The television has long since been replaced but this meter still sees frequent use.  It has a very limited range of voltage or resistance but that is all that is required to find shorts in Trackwork or a quick check on some simple project

 

Martel Meter V1_A

There are several panel meters available including this digital version.  While these types are typically sold as voltage or Ammeters, A voltmeter CAN be used to measure amps

 

This meter kit is not quite as fast or accurate as a commercial grade meter but is extremely versatile.  The PC board is designed so that it can be cut in half below the display and folded for tight configurations.  There are two versions of this display used in hundreds of meter designs, One for mounting as shown and One for mounting on the other side of the PCB.  The meter also has a breadboard area and instructions to show how the same meter can measure volts OR amps and even resistance in almost any range with the decimal point properly placed

Note the double row of holes in the picture to the left in the middle of the board.  This is where the board can be cut and reconfigured as shown below. 

Two of these meters are used in the Bench-top power supply shown below in a wooden case.

                 

 

This third dual-meter combination is one of several series of standard panels meter meant for instrumentation such as the volts and amps of track power.  Some of the less expensive of this series costs less then the older mechanical meters.  It is more rugged and less prone to damage due to wiring errors.

 

 

 

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Sometimes it is handy to have a way to inject some sort of signal at one end of a circuit to see what happens at the other. Both of these generators use about the same parts And form sign, square and triangular waves Ranging from one wave every ten seconds To 100,000 waves per second.

 

This particular generator is a kit that can be run from an internal batter or  external power.

        

This generator was built from spare parts, it is designed to run from 9 to 18v AC or DC and can supply five volts to a project under development.  The jumpers to the extreme right control the frequency, the LED flashes to show the power is on.  The header at the bottom delivers all three waveforms simultaneously.  This device is not elegant but it works quite nicely and takes almost no room on a desk top.

This dual channel oscilloscope doesn’t see much use but it can be handy for more advanced projects or just to satisfy curiosity.  It is the most sensitive way to find glitches and fluctuations of voltage.

   

         List of kit vendors for these and many other electronic devices

 

Cana Kits

Elenco

Jameco

 

 

 

 

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A test track can be bulky and occupy precious desktop space when testing electrical circuits

A simple motor can simulate the characteristics of an engine.  This unit was used to test

 

    

A test track  is a must-have when it comes to engines.  The most obvious reason is for testing an engine mechanically after lubrication or replacements of parts.  It is also needed for cleaning wheels after running on dirty track and testing any electronics such as DCC decoders.  It also comes in handy for running in new engines.

 

Test Track

  

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Over the course of years I have grown tired of building a power supply for each project.  Eventually I got smart and built a number of modules that can be re-used for every new project.  This is a simple 5v power supply for prototyping small projects.  The on-board regulator is good for only 1/10 of an amp and then only for short periods.  Adding a heat sink to the regulator would allow surges to 1/5 amp or 1/10 amp continuous.  This is more than enough to power 5-10 typical integrated circuits

     

This 35 volt 5 amp switching regulator was designed to work with capacitor-discharge switch machine control.  The switching regulator is a bit more complex and requires the large doughnut-shaped inductor to work but it is highly efficient.

 

I chose to wind my own transformers which is not that difficult and yields the ultimate power.  A single turn can effect the output but a small potentiometer makes peak performance a cinch.

Switching regulator

Power supply for testing

The heavy-duty 10-volt supply shown here is used for larger projects that already have part of their own power supply.  I am a firm believer in safety and keep all transforms contained in a separate fire-proofed cage on the layout and well-insulated on the work bench. 

 

 

This little gem is actually little more than a glorified power pack.   I use it to power up many projects as well as to power a test track when working with locomotives. 

   

      

This is a handy little desktop I use with many projects.   Each section is separate from the others so like the above prototyping board, a wide variety of power supply configurations are possible including either an internal or external transformer, full wave or half wave rectifier, a push button for “smoke” testing new circuits and a switch to turn a circuit on or off.  It also contains a Voltmeter, Amp meter, three separate voltage supplies, and a battery charger For nine-volt batteries.  The external AC sockets are on their own switch.  In short, every thing you need to power and test a circuit under development

 

 

 

 

    

 

    

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Bat_02_AT

 

 

   

About Batteries

Notes on batteries

 

Battery vs. cell

 

Non-chargeable

Carbon zinc

Alkaline

coin

 

 

 

Chargeable

Lead/acid

lithium

NiCad

NiMH

Recharge at capacity for two hours

 

Bat_03_AS

 

 

 

Rechargeable batteries a bit less than non rechargeable

Rule of thumb is to charge at capacity rating for two hours

i.e.  a 9v 175ma hour battery is charged at 175 ma for two hours

stop if battery gets warm

 

 

A new or fully charged battery supplies certain voltage

This voltage drops

With load

As battery discharges

 

       

  

 

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This charger is designed to charge up to six batteries at once.

          Switch selects which battery to monitor (or none)

          Charges 9v 175 ma battery in about four hours

 

 

    

 

     

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         First is testing devices

         Powered by batteries it is checking

              No display, batteries are dead

              Otherwise it will indicate battery charge

              Normal charge is between seven and eight volts

 

 

 

This is a much simpler monitor

     Uses batteries

     Normal charge is about eight volts

 

 

     

      

 

     

   

    

 

   

 

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Bob Van Cleef, MMR

Last update   08/02/2012