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Q1 gw_product_detail_bar.png gw_product_detail_bar.png How to verify fuses and circuit breakers at the most appropriate cost?

Testing fuses and circuit breakers requires transient current to test whether the operation is normal.

 

  • It is a design issue when a circuit breaker fails to disconnect.
  • It is a quality issue when a circuit breaker disconnects abnormally.

 

GW Instek electronic loads with turbo mode can help users verify these two issues at the most appropriate cost.

 

Turbo mode can provide double the rated current or power for a short period of time (1 second).

 

Electronic loads with turbo mode include:

 

  • GW Instek brand: The AEL-5000 series
  • Prodigit brand: The 3310G series, the 3350G series, the 3270 series, and the 3282 series

 

Other applications of turbo mode: AC power short circuit, OCP and OPP tests

 

More Porduct information: DC Electronic Load

 

Q2 gw_product_detail_bar.png gw_product_detail_bar.png Does the DC mode of the AC power supply have the constant current (CC) output of the DC power supply?

The DC mode of the AC power supply does not have the constant current (CC) output of the DC power supply.

 

The DC mode of the AC power supply can only provide constant voltage (CV) output. When the DC power supply is overloaded, it will become a constant current (CC) output. When the DC mode of the AC power supply is overloaded, the output will stop.

 

 

Q3 gw_product_detail_bar.png gw_product_detail_bar.png Decrypting the Zero Voltage Startup of Electronic Loads

The basic component of an electronic load is a MOSFET, which is a voltage-controlled variable resistor.

 

The electronic load is an important device for testing the transient response of the power supply. If we simplify the electronic load into a MOSFET, when the MOSFET is connected to the power supply, the voltage of the power supply must reach the MOSFET Vds voltage before current will flow. Therefore, the electronic load cannot start at zero voltage from its basic structure.

 

If your application requires zero voltage startup, how do you accomplish this application?

 

Only a power supply is required to be connected in series to offset the voltage change of Vds to start an electronic load at zero voltage.

 

Possible applications: Supercapacitor, fuel cell

 

Q4 gw_product_detail_bar.png gw_product_detail_bar.png What conditions will the power supply activate over-voltage protection (OVP)?

The power supply overvoltage protection (OVP) is designed to protect the device under test (DUT) or the circuit under test (DUC) from excessive voltage.

 

Three possible overvoltage (OVP) scenarios are provided below.

 

Scenario 1: Users forgot that the over-voltage protection was set in the last project, and the voltage of this test project is higher than the over-voltage protection setting value.

 

For example: the OVP of the last project was set to 12.5V, and the required voltage for this project is 15V. The set output voltage is higher than the over-voltage protection of 12.5V, so the power supply starts the protection mechanism to stop output.

 

Scenario 2: After remote compensation is connected, the output of the power supply exceeds the overvoltage protection setting value due to compensation.

 

For example: the working voltage of the circuit is 12V, and the overvoltage protection is set to 12.5V. Due to excessive wire loss, a voltage drop of 0.6V is caused on the wire, resulting in the voltage of the DUT being only 11.4V. The power supply starts to compensate. After compensation to 12.5V, the DUT is 11.9V. After further compensation, it exceeds the overvoltage setting value of 12.5V, so the power supply activates the protection mechanism to stop output.

 

Scenario 3: Due to the inductance of the test wire, at the moment when the power supply is switched on or off or when the programmable voltage changes, the stray components on the wire cause LC resonance, leading the transient voltage of voltage change to exceed the OVP protection voltage setting value.

 

 

Q5 gw_product_detail_bar.png gw_product_detail_bar.png How to improve the test throughput of programmable power supplies?

During production line testing, the programmable DC power supply provides voltage, current, and test time. These three programmable variables allow the complex production line testing process to be automated. However, if you want to further improve the test productivity after automation, you must understand the design and special features of the programmable power supply.

 

First we need to understand the output characteristics and load effect of the DC power supply.

 

In order to provide a stable DC output, the DC power supply has a capacitor on the output to perform filtering operation. The capacitor does not allow the voltage to change instantaneously, so when you want the voltage output to change, the DC output filter capacitor will cause this change time application in dilemma. The smaller the output ripple is, the slower the reaction speed to voltage changes is.

 

The output voltage should become larger: faster when there is no load and slower when there is a load. A life case: A car full of passengers and a car without any passengers climb a hill. Under the same accelerator conditions, the latter climbs faster and the former climbs slower.

 

The output voltage should become smaller: slower when there is no load and faster when there is a load. A life case: A car full of passengers and a car without any passengers go downhill. When the accelerator is not stepped on, the latter goes downhill slowly, but the former goes downhill quickly. When the power supply provides the bleeder resistor function, the bleeder resistor can be used to increase the time for the voltage to decrease.

 

If the power supply needs to perform rapid voltage changes (100u second level), it can be achieved by using the DC mode of the AC power supply, such as GW Instek's ASR-2000 series and ASR-3000 series AC/DC dual-purpose power supplies.

 

If rapid changes in current are required, an electronic load can be used to draw the source to force the power supply to provide rapid current.

 

In addition to the above issues, the hardware setting time and the computer control interface adopted (GPIB, RS-232, USB, LAN) will all affect the programmable voltage change time.

 

More Porduct information: AC/DC Power Supply

 

Q6 gw_product_detail_bar.png gw_product_detail_bar.png Checking steps for power supply with no output

Step 1:

Check whether the AC input of the power supply is normal? Is it because the power plug strip controlled by a switch was not turned on or was turned off by a colleague without noticing. Check whether the display on the power supply shows anything. If not, check whether the fuse of the power supply is burned out.

 

Step 2:

After confirming that the power input is normal, set the output voltage and current of the power supply. The two cannot be 0 (especially note that the current cannot be 0). If you find that the set value cannot be displayed, some models of GW Instek provide a key lock function to ensure that the set value is not accidentally changed during the test.

 

Please confirm whether the model you are using has this function. If so, please confirm the Key Lock light is off. If the Key Lock light is on, please unlock it first. If it still cannot be set, please confirm whether the power supply is connected to the computer. If the computer is connected, the remote control mode will cancel the local operation.

 

Step 3:

If the power supply has an output control switch, please press on. If the power supply has an output control switch, there will usually be a light indicating that the output is on.

 

Step 4:

If the output control switch is turned on but the light does not light up (the light may be faulty, but the power supply still has output), please use a multimeter with a voltage range to measure the output of the power supply. Several power supplies from GW Instek have an on/off delay timer function. Please also pay attention to whether there is a time delay in the output due to this function being turned on.

 

If after following the above steps, the power supply still has no output, please contact your nearest GW Instek Service Center to arrange for the instrument to be sent for repair.

 

Service Support

 

More Porduct information: DC Power Supply

 

Q7 gw_product_detail_bar.png gw_product_detail_bar.png Output modes of DC power supply, constant voltage mode (CV mode) and constant current mode (CC mode)

The output of most DC power supplies provides a set voltage, which we call constant voltage mode (CV mode). Using "set fixed output voltage" to describe it can better express the overall meaning. At this time, the current of the power supply changes with the load.

 

However, this maximum fluctuation current cannot exceed the maximum design current of the power supply (to meet the application and price design goals) or the maximum set current (to protect the circuit under test). Therefore, once the load current exceeds any of the above current values, the power supply output will switch from CV mode to constant current mode (CC mode).

 

Taking DC power with a maximum design voltage/current of 30V/3A as an example. When the load does not exceed 3A, the power supply is in constant voltage mode, and the set output voltage can be 0~30V (based on the minimum setting resolution). Taking the output as 12V as an example, as long as the load does not exceed 3A, the ideal value of the output voltage is fixed at 12V (the unideal output is affected by specifications such as output accuracy, ripple/noise, line voltage regulation rate, load regulation rate, etc.), and the current value varies depending on load.

 

Once the load exceeds 3A (according to Ohm's law 12V/3A = 4 ohms, when the load is lower than 4 ohms, the load will exceed 3A), because the power supply can only provide 3A, it switches to constant current mode and the current is 3A, and the output voltage varies depending on the load.

 

The relationship between load, current and resistance is as follows: Generally, the reason why the current does not reach the set current is that the resistance is not small enough.

 

Large load = large current = small resistance; small load = small current = large resistance

 

How to set the maximum current:

 

  • Knob setting: The output must be short-circuited to see the current reading. It is recommended to turn the knob to the state where the current is 0. If the knob is at the maximum current position, there may be sparks at the moment the output is short-circuited (possible shock). Slowly turn the knob from the position where the current reading is 0 to the required maximum set current.
  • Button setting: Just use the number and unit buttons to input the required maximum set current.

 

More Porduct information: DC Power Supply

 

 

Q8 gw_product_detail_bar.png gw_product_detail_bar.png How to use a DC power supply to generate positive and negative voltages to test a dual-channel positive and negative low dropout voltage regulator?

Dual-channel positive and negative low-dropout voltage regulators require positive and negative voltages for excitation. Three methods of generating positive and negative voltages are provided below.

 

Method 1: If you only have two single-channel DC power supplies, the wiring method is as follows:

 

 

Method 2: If you have a dual-channel DC power supply but there is no automatic wiring switch inside, you need to connect it externally.

 

 

Method 3: If you use GW Instek's dual-channel power supply, it has an automatic wiring switch.

 

Q9 gw_product_detail_bar.png gw_product_detail_bar.png The devil is in the details, on the design details of dual-channel DC power supplies

They all claim to be dual-channel power supplies, but the devil is in the details, and details determine value.

 

There are many dual-channel DC power supplies on the market. In addition to providing two independent power supplies, dual-channel power supplies also have the following three applications due to their dual-channel design:

 

  • Application 1: Series and parallel connection between channels. Series connection can meet the requirement of larger voltage applications, and parallel connection can meet the requirement of larger current applications.
  • Application 2: Provide positive and negative voltages to test the DUT, such as a dual-channel positive and negative low dropout voltage regulator.
  • Application 3: Simultaneous output of dual channels to excite the DUT that requires synchronous action.

 

The above three applications will have different impacts on users due to different designs. The followings are three designs on the market.

 

When used as separate channels, no difference can be seen between the three designs.

 

 

Applications in parallel

 

 

For design 1, when considering series and parallel applications, it can only be used in series but not in parallel. Design 2 requires users to spend more time on external wiring. GW Instek's automatic wiring design allows users to easily complete series and parallel applications.

 

Applications in series

 

 

After discussing the application 1 of series and parallel connections between channels. Next, let’s talk about application 2: providing positive and negative voltages to test the DUT.

 

 

Finally, the application of synchronous stimulation

 

The actual measurement comparison is between the output start-up and output shutdown transients of GW Instek's GPP series and a different brand. When outputting the same voltage, the inter-channel delay of GW Instek's GPP is extremely low (typical value is 0.1ms), while the other brand has a 12ms channel delay when turned on and there is a 100ms channel delay when turned off.

 

 

 

Summarize:

 

In addition to attaching importance to the details of multi-channel applications, GW Instek's GPP series multi-channel DC power supplies also provide the following features:

 

  • Electronic load
  • Sequential output
  • Data collection/logging function is only available on channel 1 and channel 2
  • Channel 3 outputs via USB Type A (only available on GPP3323/3060/6030)
  • Series and parallel automatic tracking/automatic wiring (not available on GPP1326 single channel)

 

Compatible with the commands of GPD-x303S series DC power supply

 

More Porduct information: DC Power Supplies

 

 

Q10 gw_product_detail_bar.png gw_product_detail_bar.png Source Measure Unit Rack Mount

GRA-450

The GRA-450 rack mount is suited for several models including GSM-20H10、PPH-1503、PPH-15XXD. The GRA-450 supports both the EIA (GRA-450-E) and JIS (GRA-450-J) standards. Incorporating a strong frame and robust design, the GRA-450 is specifically designed to hold one and two units and fits in a standard 19” 2U rack.

GRA-450

Q11 gw_product_detail_bar.png gw_product_detail_bar.png Power Supplies and Load Rack Mount Kit (1)

GRA-401 for PPE-3323/PPT-1830/PPT-3615

PEL-002 for PEL-2000 series

GRA-403 for PSH-series

GRA-407 for PSM-series and PST series

GRA-413-J (JIS) for PEL-3211/3211H

GRA-408 for PSS-2002/3203

GRA-409 for APS-1102A

GRA-410-J (JIS) for PSW-series

GRA-410-E (EIA) for PSW-series

GRA-414-J for PEL-3021/3021H/3041/3041H/3111/3111H/3031E/3032E

 PLR1

Q12 gw_product_detail_bar.png gw_product_detail_bar.png Power Supplies and Load Rack Mount Kit (2)

GRA-413-E for PEL-3221/3211H

GRA-423 for APS-7050/7100/7050E/7100E series

GRA-418-J (JIS) for PSB-1000 series

GRA-418-E (EIA) for PSB-1000 series

GRA-424 for PSB-2000 series

GRA-429 for APS-7200 series

GRA-431-J (JIS) for PFR series

GRA-414-E (EIA) for PEL-3021/3021H/3041/3041H/3111/3111H/3031E/3032E

GRA-424 for PSB-2000 series

GRA-419-J (JIS) for PCS-1000i

GRA-419-E (EIA) for PCS-1000

GRA-428 for PSP series

GRA-430 for APS-7300 series

GRA-431-E (EIA) for PFR series 

PLR2

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