Win a Tenma Power Supply

James's videos have been the guide on my path to learning a new world.  My background has always been software and hardware hacking, but never hardware creating.  A year or so ago I set out to try and give myself a mini-EE education.  I read and learn as much as possible everywhere possible.  This power supply would become the very staple of my bench and I can finally give up using the ever so inaccurate DIY power supply cobbled together from a PC power supply.  Imagine an actual variable power supply.  No more batteries.  No more dirty power from the old PC supply. 

Thanks for making you videos James. 

Cheers

Mark

powering a memes oscillator foe a micro-fluidic device that creates water droplets, project for drug fabrication project

TURN IT INTO AN LED ZENER DIODE TESTER.

I would like to use the current limiting capabilities of the Tenma  Power Supply to test my large collection of Zener Diodes and Raw LEDs. This can be done by shorting the output at a low voltage setting and adjusting the current limit to a desired level say 25 mA for the Zeners or 10 mA for the LEDs. Next the Zener or LED is hooked to the output and the voltage is slowly raised until the current limit is met. At this point the Zener value can be read from the Power Supply Voltage meter. In the case of the LEDs the energy level of the junction is indicated by the voltmeter. This can be helpful if one is trying to match LEDs for series or parallel circuits.

John

There are some typical lab usages of lab power supply for RnD needs:

- research the actual parameters and characteristics of electronic components and electric appliances, e.g. analyzing the emitted spectrum and luminosity of lamps and LEDs under different powering conditions.

- do test and raw calibration of just soldered equipment in the home lab, e.g. scope or multimeter.

I don't think wire resistance changes much at DC, even if it heats up it isn't a big concern, I just like the convenience of not having to calculate the voltage drop at whatever current the target device consumes.

There is also always the possibility that the high current will expose a poor wire joint that wouldn't be detected by a DMM.

How much have you seen the resistance to change when increasing the current from close to 0 up to 1A?

Good point. A good DMM should be able to measure milliohms well enough to get cable resistance, which is pretty useful.

However, even if it is a fancy 4-wire DMM, you would still need to calculate the voltage drop. And a DMM doesn't stress the wire with the full current it is expected to carry. Neither instrument is ideal, but if I had a choice I would use the power supply solution. Even purpose-built cable testers are not ideal, since they often require set-up and boot time and I am not aware of any that have all the USB connectors built-in. Ultimately it boils down to what instruments you have on hand and your preferences of which to use.

Or alternatively use a DMM

amerrigan , have an experience you want to share?

Here are a few real-life examples I would use it for.

1) Multi-chemistry battery charger. There are many types of batteries on the market and each type requires special charging conditions. I have single cells and assembled packs of Ni-MH, Li-ion and Li-Polymer accumulators in various projects and at work. Also Pb accumulators in a car and a scooter. There are special chargers for each type, but CV and CC modes are OK to charge all the types. Of course the form factor is bigger than a dedicated charger, but if you know the specifics of your accumulators, you can increase or reduce the charging speed.

Recently, we saved a colleague who came to work on a motorcycle, but later couldn't start because of a drained battery. Using a power supply, not only we charged the battery so he could start the engine, but also kept all the electronic circuitry running. Some new cars refuse to start after a DIY accumulator change.

2) Measuring capacitors leakage current

As described in baldengineer's tutorial https://www.element14.com/community/community/element14-presents/workbenchwednesdays/blog/2019/06/19/measuring-an-aluminum-electrolytic-capacitors-esr . At work, we use large electrolytic capacitors during manufacturing of some of our devices, in order to test the low power modes of the device. Every capacitor used this way needs to be measured for the leakage current so the devices' low power mode is distinguished from a capacitor self-discharging.

3) Cooler/heater for component specification testing

There are many applications that will benefit from a regulated power delivered to a Peltier module.

I used this a few times already. I needed to overclock a CPU for a while and used Peltier module inserted between the CPU and a heat sink with a fan.

A general purpose heater or cooler might be built the same way - just attaching a large CPU heat sink with a fan on one side and a heated/cooled object on the other. This setup can be used to test leakage current of various components, mainly (but not limited to) semiconductors. For example microcontrollers can have 1000x higher leakage current at 100 Centigrade, compared to a consumption specified in the datasheet for 25 Centigrade.

4) Flicker-free LED lightning

A few years ago, LCDs started with tubes' back light and later moved to LEDs. Still, there are cheaper back lights in LCDs in stand alone-monitors and laptops that use PWM dimming. The same is situation is now with LED lightning. If the lights are dimmable, they use PWM. Higher frequencies are used so the flickering effect is reduced, but there is nothing more comfortable linear power dimming. This requires building your own power supply (or at least I haven't seen a commercially available solution).