Electrical Test & Measurement · Electrical Test Equipment
Bench DC power supply in a narrow 80 mm case, with 15 to 150 V and 2 to 20 A models, four-digit voltage, current and power readout, and preset without shorting the output.
eTM-152MF (5 models) ·
A repair bench has less room than a laboratory, and most bench supplies are built for the laboratory. This one is 80 mm wide, which is roughly the width of a phone lying down, and it still carries a four-digit display and two knobs.
Eight models share one chassis and one control layout. They differ in maximum voltage and maximum current, and the pairing is not proportional: the range includes a 15 V unit at 20 A and a 150 V unit at 2 A, because those are the two shapes of work a bench actually sees.
The front panel holds a display with three rows, one each for voltage, current and power, with a C.V. and a C.C. indicator beside them and a lock indicator below. Two knobs set voltage and current, an ON/OFF key controls the output, and the positive and negative terminals sit at the bottom with an optional quick-charge USB socket between them.
The rear carries the mains switch, the fan, the inlet and the fuse, plus an RS-485 socket when that option is ordered. The case is ventilated on both sides and stands on four feet, so it can sit under a shelf rather than needing clear space above.
The output stage holds one of two conditions. In constant voltage it regulates the terminal voltage to the set value and lets the current fall where it will; in constant current it regulates the current and lets the voltage fall. The crossover is automatic, and the two indicators tell the operator which condition is active — which is the single most useful piece of information on the panel when a device under test starts to draw more than expected.
Setting is done before the output is enabled. That is why there is no need to short the terminals to set a current limit, a routine that damages leads and startles the user in equal measure. The set values are held while the output is off, and the lock prevents them being moved by a hand brushing a knob.
The meter reads the output back rather than repeating the set value, so a sagging supply or a lead with too much resistance shows up as a difference between the two. Voltage and current are read at their own resolutions, and both are quoted with a warm-up condition, because a cold instrument drifts.
Cooling is proportional. The fan follows the output power, which keeps a lightly loaded supply quiet and only spins up when the heatsink needs it. On a bench where the supply runs all day at a fraction of its rating, that is the difference between a tolerable room and an irritating one.
Take the voltage and the current separately. A device that needs 12 V at 8 A is not served by a 30 V 5 A unit, and a device that needs 120 V at 200 mA is not served by a 30 V 20 A unit. The models are arranged along both axes for that reason.
Then look at the load. A resistive load is undemanding; a motor, a relay coil or a board with a large capacitor draws a surge at switch-on that the current limit will treat as a fault. Where that happens, the limit has to be set above the surge, not above the running current.
Consider the ripple figure at the voltage you intend to use. It rises across the range, and a supply chosen for its voltage headroom may be the noisiest option for a sensitive measurement. If the work is audio or sensor front-end, the lower-voltage models are the quieter ones.
Finally, decide the options at the order. The USB charging socket and the RS-485 port are factory fittings, and the mains configuration — fixed 110 V or a changeover — has to match the site. Send the voltage, the current, the nature of the load and the mains available, and a model can be proposed.
A four-digit display is not a four-digit measurement. The accuracy figure includes a digit count, and at the bottom of a range that count is a larger fraction of the reading than at the top. A 0.1 V setting on a 150 V unit is a coarse adjustment by design, not a fault.
The current limit protects the supply and the device, but it does not protect a device from itself. A board with a short will sit at the limit with the voltage collapsed, and nothing on the panel says whether that is a soft start or a fault. Reading the voltage row while the current row is pinned is the only signal available.
Ripple is quoted at the output terminals. A long lead with clip ends adds inductance and resistance, and a load that switches quickly will see more disturbance than the figure suggests. Twisted pairs and short leads do more for a sensitive load than a lower ripple specification.
The supply is a two-quadrant source in the sense that it sources current only: it cannot sink. A battery or a charged capacitor connected to the terminals will push current back into the output, and a supply that is switched off with a charged load attached is not protected by its own limit. Where sinking matters, an electronic load is the instrument to reach for.
Every value below is taken from source documentation. Where a parameter is not stated in the available material it is marked as information required rather than estimated.
| Maximum voltage | 15 V on the 152, 155 and 1520 models; 30 V on the 305F and 3010MF; 60 V on the 605MF; 100 V on the 1003MF; 150 V on the 1502MFStandard |
|---|---|
| Maximum current | 2 A on the 152MF and 1502MF; 5 A on the 155MF, 305F and 605MF; 20 A on the 1520MF; 10 A on the 3010MF; 3 A on the 1003MFStandard |
| Voltage setting resolution | 10 mV below 100 V, 0.1 V at 100 V and aboveStandard |
| Voltage readback resolution | 10 mV below 100 V, 0.1 V at 100 V and aboveStandard |
| Voltage setting and readback accuracy | 0.1% + 5 digitsStandard |
| Current setting resolution | 1 mA below 10 A, 10 mA at 10 A and aboveStandard |
| Current readback resolution | 1 mA below 10 A, 10 mA at 10 A and aboveStandard |
| Current setting and readback accuracy | 0.2% + 10 digitsStandard |
| Voltage ripple | 10 mVrms on the 152MF, 155MF, 1520MF, 305F and 3010MF; 15 mVrms on the 605MF; 18 mVrms on the 1003MF; 20 mVrms on the 1502MFStandard |
|---|---|
| Current ripple | 10 mArms on the 152MF, 155MF, 1520MF, 305F and 3010MF; 15 mArms on the 605MF; 18 mArms on the 1003MF; 20 mArms on the 1502MFStandard |
| Load regulation below 10 A | 0.1% of maximum voltage + 5 mVStandard |
| Load regulation at 10 A and above | 0.2% of maximum voltage + 5 mVStandard |
| Line regulation | Same figures as load regulation, given for both in one lineStandard |
| Voltage temperature coefficient | 0.02% + 3 mVStandard |
| Current temperature coefficient | 0.02% + 3 mAStandard |
| Protection fitted | Overvoltage, overcurrent, over-temperature and short circuit, described as five-fold protection although four are namedInformation required |
|---|---|
| Crossover | Automatic between constant voltage and constant current, with an indicator for eachStandard |
| Preset | Voltage and current set before the output is switched on, without shorting the terminalsStandard |
| Output switch | Front-panel ON/OFF keyStandard |
| Key lock | Panel lock with an indicator, to stop the set values being changed by accidentStandard |
| Warm-up | Ten minutes before the accuracy figures applyStandard |
| Mains | AC 220 V ±10%, 50 Hz; a fixed AC 110 V input or a 110/220 V changeover can be specifiedInformation required |
|---|---|
| Cooling | Forced air, fan speed following the output powerStandard |
| Front panel | Two adjustment knobs, output ON/OFF key, positive and negative terminals, optional quick-charge USB socketStandard |
| Rear panel | Mains switch, fan, inlet, fuse holder and an optional RS-485 socketStandard |
| Dimensions | 80 mm wide, 150 mm high and 230 mm deep, measured by handStandard |
| Weight | About 1.95 kgStandard |
| Supplied accessories | Mains lead, one 5 A clip lead and a manualStandard |
| Model | Configuration | Key ranges | Availability |
|---|---|---|---|
| eTM-152MF | 15 V, 2 A | 0 to 15 V; 0 to 2 A; ripple 10 mVrms | Smallest output |
| eTM-155MF | 15 V, 5 A | 0 to 15 V; 0 to 5 A; ripple 10 mVrms | More current at low voltage |
| eTM-1520MF | 15 V, 20 A | 0 to 15 V; 0 to 20 A; ripple 10 mVrms | Highest current in the range |
| eTM-305F | 30 V, 5 A | 0 to 30 V; 0 to 5 A; ripple 10 mVrms | General bench work |
| eTM-3010MF | 30 V, 10 A | 0 to 30 V; 0 to 10 A; ripple 10 mVrms | General bench work with more current |
| eTM-605MF | 60 V, 5 A | 0 to 60 V; 0 to 5 A; ripple 15 mVrms | Higher voltage |
| eTM-1003MF | 100 V, 3 A | 0 to 100 V; 0 to 3 A; ripple 18 mVrms | Above the 100 V metering step |
| eTM-1502MF | 150 V, 2 A | 0 to 150 V; 0 to 2 A; ripple 20 mVrms | Highest voltage in the range |
Certifications are only published once a certificate copy can be produced, so this section is deliberately empty rather than populated with assumed approvals. Tell us which approvals your application requires and we will confirm what is available for this instrument.
The following are required for a complete specification but are not stated in the documentation supplied to us. They are listed rather than estimated:
Because the current setting is the limit, not the value. On a repair bench the supply is often used to bring a board up slowly, and the current limit is what stops a short from turning into a burn. Setting it before the output is switched on means the limit is already in place when the device first sees power, rather than being adjusted afterwards.
The metering step. Below 100 V the setting and readback resolution are 10 mV; at 100 V and above they are 0.1 V. The accuracy specification itself does not change. That is worth knowing when a low voltage has to be trimmed precisely on a 100 V or 150 V unit: the resolution, not the accuracy, is what limits the adjustment.
The highest voltage and the highest current the work needs, taken separately rather than as a single power figure, since the models are chosen by both; whether the load is resistive or inductive; the mains supply available on site; and whether the RS-485 interface or the USB charging socket is required, as both are options rather than standard fittings.
Related products
QJ300N (4 models) · Electrical Test Equipment
Linear bench supply, 30 V at 3 or 5 A, with 1 mVrms ripple, fine and coarse adjustment on one knob, three stored settings and an option for USB control.
KS9830 (5 models) · Electrical Test Equipment
Five-model battery simulator range covering 20 to 48 V and up to 20 A, with 1 mV and 1 mA setting resolution, four-wire remote sensing and readback of voltage, current and power.
CH6321A (5 models) · Electrical Test Equipment
Programmable DC electronic load with 150 V and 500 V inputs, 60 to 240 A, 600 to 1500 W, six load modes and battery, dynamic and OCP test functions.
Send the configuration you need and we will confirm availability, lead time and terms. Minimum order quantity is 1 pc.
Request for quotation
Send the technical detail and we will confirm availability, lead time and terms. In-stock items ship within 48 hours; customized specifications typically take 2-10 days. Minimum order quantity is 1 pc.