How to Use a Soldering Iron

Soldering is the process of melting a metal on other metal components to bind the two components together. The most common tool used for this is called a soldering iron.
Soldering is not the same as welding. When you weld something, the components are directly melted together without using solder. Solder is a softer metal with a lower melting point. This allows the components to be connected without using the high temperatures associated with welding and it preserves the integrity of the components. Because solder is conductive, it is widely used in electronics.

Rolls of solder


Using solder to bind things

Solder is the actual material used when binding things together with a soldering iron. Solder has traditionally contained lead, but it is gradually being phased out due to health concerns. Most lead-free solder is slightly more difficult to use than leaded varieties; when melting unleaded solder, the soldering iron needs additional time to recover from heat loss.


Manufacturers of soldering irons use various techniques to make their soldering irons work better with lead-free solder. One strategy is to make the soldering iron heating element more powerful, which helps keep the soldering iron tip at a constant temperature. Other techniques include assembling the heating element and the soldering iron tip as a single contiguous element in order to transfer the heat more rapidly and therefore help maintain the tip temperature.


Using a soldering iron to heat and melt the solder

Most low-priced soldering irons typically heat the tip between 800 and 900 degrees Fahrenheit, so be very careful when using a soldering iron. More advanced soldering irons include a heat control so the user can select a specific temperature for different projects and types of solder. It is important to keep the tip of the soldering iron clean while using it. Common practice is to use a wet sponge to keep the tip cleaned. Clean the tip before you start soldering and continue to clean the tip as you continue the soldering process.


Heat the component, flow the solder

Touch the soldering iron tip to the component you want to solder. After a second or two, introduce the solder to the joint area. The heat will conduct to the solder and cause it to flow. This entire process should only take 3 or 4 seconds, but it is important for the solder to flow to ensure a good electrical contact. If the solder looks like a ball or is lumpy, it is likely a “cold solder joint” and will not conduct electricity. If this happens, reintroduce the soldering iron to get the solder to flow in order to create a good electrical contact


Practical applications for a plastic project box

When Circuit Specialists moved to our new building in Tempe, AZ we noticed our communications closet was getting a bit warmer than we wanted it to be. Rather than spending the time and money needed to route an air conditioning duct into the closet, we decided that just getting some air from the room outside moving through the closet would reduce the temperature by a few degrees, which would be sufficient in this case.

Door fan 1Door fan 1a

There were already two vents installed in the closet door, so we gathered a few parts we stock and went to work. We first mounted two 12 volt DC fans to the upper vent (we also drilled extra mounting holes for two more fans, in case we need them later). We then used a 12 volt wall mount power supply and a small SPDT miniature toggle switch to power the fans.  We mounted the switch and an LCD digital temperature display  — for monitoring the exact temperature — inside a PB-1P plastic project box and attached it outside the door.

Door fan 2Door fan 2a

The DTM0503 temperature display that we used is normally powered by a 1.5 V battery, but we chose to power it with the same DC power supply used for the fans, which required adding a few components to the mix. We used a 1N4741 zener diode soldered in series to the battery terminal on the back of the panel meter to bring the 12 volts down to the 1.5 volts required for the temperature display.

Door fan 3Door fan 3a

Now that everything is installed, we can see at a glance what the temperature inside the communications closet is and turn the fans off to conserve energy whenever possible.

Door fan 4


Wireless inspection cameras are terrific tools for contractors and building inspection professionals as well as do-it-yourselfers doing repairs and renovations around the house. Inspection cameras have become very affordable in recent years and are becoming standard equipment for HVAC repairmen, electricians, mechanics, and plumbers. Any situation that requires observing what is happening in an otherwise inaccessible area can be made much easier with a good inspection camera.

Choosing an Inspection Camera

Let’s start by ruling out any inspection camera that is designed with a 1 meter camera shaft. What good is an inspection camera that doesn’t reach what you want to see?  A good wireless inspection camera should have a shaft long enough to see around corners and underneath objects. A camera with a 3 meter camera shaft is simply more effective than one limited to just 1 meter.

Furthermore, a good inspection camera needs to provide good lighting to produce a good image of the target. Adjustable bright white LEDs are usually placed near the camera head for this purpose. If you do not have adequate light, the image quality will never be good enough. The images or videos captured from an inspection camera should be clear and high quality.

The DeWalt DCT411S1 captures both still photos and video and stores them on a micro SD card. The Bosch PS91-1A is also quite popular and receives good reviews. Prices for these units start at around $200. Ridgid sells an inspection camera with a 200’ reel for around $5,000 for demanding professionals and other high-end users.

A 200’ reel is complete overkill for an average user. Your typical handyman or mechanic can do very well with a wireless inspection camera with a 3 meter shaft as long as it provides sufficient lighting and produces a clear image or video.

Wireless inspection camera

New Trend in Inspection Cameras: High-Definition Cameras that Work with Your Smartphone or Tablet

The Aardvark HD3M waterproof wireless inspection camera is a recently developed camera design that interfaces with the user’s iPhone or Android smartphone or tablet. This inspection camera connects to the user’s wireless device via WiFi and features the desired 3 meter camera shaft length. The camera unit itself acts as a WiFi access point, so it may be used in remote areas where WiFi isn’t available.

The waterproof camera head provides high-definition images or videos (2 megapixel/1280×720) directly to your wireless device and the six adjustable high-intensity white LEDs placed at the camera head provide plenty of light. Most smartphones and tablets have a large high-definition screen, and since the images and videos are stored on the user’s wireless device, it’s very simple to email or text the files virtually anywhere. Perhaps more importantly, since the Aardvark HD3M inspection camera doesn’t have a video screen and doesn’t need a storage card, it is available for a much lower price than traditional inspection cameras, yet it provides superior performance compared to units that cost up to three times as much.

This wireless inspection camera includes a hardshell carrying case and a 3 meter flexible shaft as well as some handy accessories. The shaft diameter is 7.0mm while the actual camera head measures 8.5mm (outside diameter). It can provide crisp still images or videos at 30 fps. The unit runs on 4 AA alkaline batteries.

Buy an Aardvark HD3M wireless inspection camera

Tech Tip: Controlling Electronic Test Equipment with SCPI

The Circuit Specialists CSI3721A and CSI3723A programmable DC electronic loads and the 3631A, 3662A, 3663A, and the 3664A programmable power supplies are fully programmable test instruments that support the standard commands for programmable instruments (SCPI) control protocol. The SCPI standard specifies a common syntax, command structure, and data format for controlling and receiving data from a wide range of test and measurement equipment.


Array 3664A Programmable Power Supply

Because the communication type is not specified by the SCPI standard, you may use GPIB, USB, RS-232, Ethernet, and several other types of cables. Most of the Circuit Specialists units offers feature an RS-232 port, but they can also be used with USB adapters or outfitted with a GPIB interface as a special order.

SCPI commands are ASCII text strings consisting of one or more keywords and one or more optional parameters. Responses to commands such as data or handshake responses can be ASCII text strings or binary data.

SCPI commands either perform a “set”, such as turning a power supply or electronic load on or off, or a “query” operation, such as reading a voltage or current value. In addition to setting and querying in a single operation, SCPI enables you to group similar commands.

Examples of simple command syntax for performing an operation on an programmable electronic load like the CSI3721A are listed below.

INPUT OFF disconnects the load from the device under test.
MODE CCL sets the CC mode.
CURR:0.5 sets current level
INPUT ON connects the load to the device under test.
MEAS:CURR? sends the actual current measured back to the PC.

The SCPI specification provides an easy-to-understand and universal method for controlling and measuring a wide variety of electronic test equipment. Earlier protocols were mostly vendor specific and required a custom user interface to allow computer controlled operation. Circuit Specialists will be providing more test and measurement equipment that adheres to the SCPI protocol in the future as we improve and expand our selection of products.

Meet Our Team: Sam Zerbib

Sam Zerbib joined the Circuit Specialists team in January 2015 and will be providing customer support as well as evaluating our test equipment and other products. More importantly, though, Sam is in charge of new product selection. Circuit Specialists is expanding into new and exciting fields like 3D printing — check out our new premium 3D printer filament — and we want your input. What new products would you like to see added to our website?

Sam studied mechanical engineering at Northern Arizona University where he specialized in thermodynamics, electronics, and mechanical engineering design, among other topics. In the past he’s worked with architects and other mechanical engineers designing heavy-duty HVAC kitchen ventilation systems.

Please send your ideas concerning new products to and he’ll get back to you as soon as possible. He looks forward to hearing from you.

Sam Zerbib portrait

Inventory Alert: Our Ship Has Finally Come In!

You may have noticed that many of our best-selling products have been out of stock in the last couple months. Circuit Specialists, along with thousands of other businesses across the country, has been seriously impacted by the West Coast port slowdown. Thankfully the slowdown has ended and we are beginning to recover and receive much needed shipments of new products. We sincerely apologize for any inconvenience to you.

If you weren’t already aware, the slowdown was a result of labor negotiations between the International Longshore and Warehouse Union and waterfront employers. The failure of both sides to reach a working contract has had a tremendous impact on the timely shipment of product into the United States. We are working hard on our end to overcome the delays this slowdown has caused to our operations.

That being said, Circuit Specialists is happy to announce that we have received our first full container shipment to our new location in Tempe, Arizona.


The West Coast ports are back in operation and Circuit Specialists has received our first full container at our new location. Fancy banner, huh?

The truck arrived early Monday morning, March 2nd, and backed into our dock. Our crew was ready and waiting to unload the full container containing power supplies and many other popular products. At our old location, we would have to unload the container onto pallets in our parking lot, sort the load, and then bring boxes into the warehouse in small lots. Yeah, that sucked.


With the new warehouse layout, we are able to quickly unload a container directly into the warehouse, where it can be sorted much faster and with less effort.


With much wider isles and a single warehouse area, Circuit Specialists expects to be able to process inbound containers much more efficiently than ever before, enabling us to ship your orders faster.


Circuit Specialists is also working hard to keep more inventory in stock in order to minimize the impact of events like the recent port slowdown.

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Using a USB Flash Drive with Hantek 1000 Series Oscilloscopes

Hantek 1000 series digital storage oscilloscopes feature the ability to store data and screen captures to a USB flash drive. However, there are limitations to the size of the flash drive that will function with your oscilloscope.

First, for the oscilloscope to recognize the flash drive it must be formatted as FAT32. Formatting with FAT32 is pretty straightforward on most operating systems.


Selecting FAT32 on a Windows computer.

We have also found that Hantek 1000 series oscilloscopes will not recognize a flash drive larger than 4 GB. We have tried both 8 and 16 GB flash drives with no success and suspect that the same results will be found with larger flash drives.


Select MS-DOS (FAT) on a Mac.

The same FAT32 requirement applies to USB hard drives as well, though the availability of traditional hard drives that small is rather limited these days.


Select FAT32 when using Linux.

Once the USB flash drive is formatted as FAT32 the Hantek 1000 series digital storage oscilloscopes will recognize it and you can save data and screen captures to it for use on a personal computer.

This formatting restriction also applies to a using a flash drive to update the firmware on the 1000 series oscilloscopes as well as loading and saving waveform data. These oscilloscopes enable you to save and recall either scope set up (vertical, horizontal, and trigger settings) or captured waveforms, which is helpful in subsequent analysis of measured signals and comparisons with new measurements. Waveforms may be saved as graphic images (JPEG or BMP) or in CSV format so that you can post-process the captured waveform data.


Hantek 1000 series oscilloscope file screen

How to Use an Enclosed Switching Power Supply

There are many applications for an enclosed switching power supply — for example, you can build a 3D printer in which the power supply controls the stepper motor used to position the print head. There are a wide range of types of switching power supplies with different voltages and current ratings to suit a variety of applications, including supplying power to the stepper motors in CNC machines.


A typical enclosed switching power supply

Another popular application for switching power supplies is in LED lighting. Simply select the appropriate voltage and current rating for the LED lighting module and connect it to the screw terminals on the power output of the power supply. Depending on the output current rating of your power supply, you can connect several LED modules in parallel to the same power supply, reducing the number of 110V connections and the overall cost.

These types of lights are great for lighting a workbench. You can find LED light modules with an aluminum channel and magnets that you can attach to the underside of your workbench’s shelf (see below). Attach three or four of these modules to the workbench and wire them all together, connecting them to a single power supply. Then connect a simple line cord to the unit and plug it into a power strip. Whenever the power strip is turned on all of the LED lights will come on. You can easily reposition magnetic lights like these to suit whatever project you’re working on.


Enclosed switching power supplies are ideal for powering LED lights.

5, 24, and 48 volt switching power supplies are frequently used in telecommunications. A 5 volt power supply is a perfect power source for power over Ethernet (PoE) injectors for the IP-based telephone equipment used in many business telephone systems. These power supplies are readily available, making it fast and easy to replace a failed power supply. They are also very cost-effective.


Using an enclosed switching power supply to supply 5 volts to a PoE injector in a telephone system.

Circuit Specialists offers a large assortment of enclosed switching power supplies rated from 3.3 to 48 volts with current ratings up to 80 Amps.

Shop enclosed switching power supplies

3D Printing: Adding, Not Subtracting

Prototyping is an essential part of the design process and until the recent invention of 3D printing, it was time consuming and could be prohibitively expensive. Designers were limited to using computer models for visualization and product development. The 3D printer is a revolution in the design and iteration process; intricate computer models and scanned physical objects can be replicated in plastic without many of the tools and materials costs of CNC mills and lathes. When building from a mill or lathe a person must begin with a block of material, often representing over two times the final product volume, and then subtract material. 3D printing eliminates much of that waste as plastic filament is melted and adds material in thin layers.

There is a seemingly endless number of 3D printer manufacturers and models, from high-precision printers for thousands of dollars to DIY printers that you can build for less than $100. Some common features of these printers are stepper motors, stepper motor controllers, power supplies, and 3D filament. 3D printers often use NEMA 17 stepper motors. 1.75mm diameter 3D filament is widely used by many different 3D printers as it is light and flexible, preventing jams at the nozzle. Thicker filaments require stepper motors that supply higher torques, such as our 4.2 kg-cm NEMA 17 stepper motor.

3D printer filament

PLA 3D printer filament is available in black, blue, brown, glow-in-the-dark, gold, green, gray, navy, orange, lime, pink, purple, light skin, translucent, red, silver, white, and yellow.

PLA vs ABS Filament

PLA (polylactic acid) is printed at a lower temperature and is less prone to warping, which makes it better for printing without a heated printer bed. Because it is derived from sugar, PLA gives off a semi-sweet smell during printing. PLA has a lower melting temperature than ABS (acrylonitrile butadiene styrene) and it is also considered more environmentally friendly, since it is derived from plants (i.e. it is a renewable resource) and biodegradable. Keep in mind that PLA’s low melting temperature makes it unsuitable for a part that will be exposed to high heat. PLA flows more smoothly than ABS, providing precise and fast printing.

ABS is a stronger plastic overall and as a result can be sanded or machined. It is printed around 225°C (PLA is printed at about 200°C). ABS is also soluble in acetone, meaning you can give a shiny finish to a 3D printed part by applying a few drops of acetone to the surface. ABS will be more resilient than PLA for a part that is exposed to the elements and high temperatures.

HIPS (high-impact polystyrene) filament is another interesting option. If you have a dual extruder, you can print with ABS and HIPS and then dissolve the HIPS with Limonene, enabling you to create intricate shapes and voids that would be impossible to make without support.

Shop PLA 3D filament

Circuit Specialists has moved

After nearly twenty-five years at our store in Mesa, Arizona, Circuit Specialists has moved to a new location.

We are now located at 819 West Fairmont Drive Suite 2 in Tempe, Arizona, closer to the heart of the Phoenix metropolitan area, which we hope will be more convenient to our local customers. Our new building has a much larger warehouse area with two loading dock bays, enabling us to receive much larger inbound shipments of merchandise.


Circuit Specialists is now at 819 W Fairmont Dr Ste 2, Tempe, AZ 85282

Our old warehouse was split into two separate areas, hindering our ability to find and pick orders. This new warehouse and dock layout will facilitate a much more efficient flow of orders to our customers and will also allow us to increase the number of products we stock, like our newest arrival of premium 3D printer filament, available in a wide variety of vivid colors. Circuit Specialists is always striving to provide faster, more efficient service for our customers without sacrificing accuracy.

If you are ever in the Phoenix metropolitan area, feel free to stop by. Our store hours remain 8:00 AM to 5:00 PM, Monday through Friday. We are on the south side of Fairmont Drive, two blocks north of Southern Avenue, between Hardy Drive on the west and Roosevelt Street on the east.

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Simply smart circuitry since 1971.