Quick answer. Decide which instruments must measure and which only need to teach. TMW-0001 to TMW-0012 is the instrument bench every other workshop relies on, and an instrument without a traceable calibration record is a teaching aid: fine for showing a student a waveform, not for a result that leaves the building. A workshop does not need every item calibrated every year. It needs one trusted reference, in practice the bench multimeter TMW-0007, kept for checking the rest on a stated interval. Then judge each item on the figure that matters rather than its headline: probe bandwidth, counter timebase, decade tolerance.
Twelve items, coded TMW-0001 to TMW-0012, make up the instrument bench that every other workshop depends on: a dual-output DC power supply and a general bench supply, portable AC and DC voltmeters and ammeters, two 100 MHz analog oscilloscopes, a bench digital multimeter, a 2 MHz function generator, a frequency counter reading to 1000 or 1300 MHz, and decade boxes for resistance, capacitance and inductance. A rheostat is listed with the resistance decade box rather than separately, so ask for it by name if you need one.
This is the range where a specification sheet is worth reading properly, because an instrument either measures or it does not. Two things decide that, and neither appears in a headline figure: whether the instrument has a calibration certificate you can trace, and whether what is connected to it - the probe, the lead, the shunt - is as good as the instrument. The sections below take both in turn.
| Code | Item | What to settle before ordering |
|---|---|---|
| TMW-0001 | Dual output DC power supply | Voltage and current per output, whether the outputs are isolated from each other, current limiting and short-circuit behaviour |
| TMW-0002 | Bench power supply | Same questions, plus whether it is fixed or variable and whether it tracks |
| TMW-0003, TMW-0004 | Portable AC and DC voltmeter and ammeter | Accuracy class, ranges, and for the ammeter the shunt or clamp arrangement |
| TMW-0005, TMW-0006 | Analog oscilloscopes, 100 MHz | Probe bandwidth supplied, tube and spares availability, number of channels |
| TMW-0007 | Bench digital multimeter | Digits of resolution, basic DC accuracy, true RMS or not, and input protection |
| TMW-0008 | Function generator, 2 MHz | Waveforms, output impedance, DC offset, and whether a logic-level output is provided |
| TMW-0009 | Frequency counter, 1000 or 1300 MHz | Timebase stability in parts per million, gate times, resolution and sensitivity |
| TMW-0010 to TMW-0012 | Decade boxes: inductance, capacitance, resistance | Tolerance of each decade, residual value at zero, and the current or voltage rating |
A workshop cannot afford to calibrate every instrument every year, and it does not need to. What it cannot do without is one instrument it can trust. Buy one instrument of the type you measure with most often - in practice the bench multimeter - with a calibration certificate traceable to a national standard, keep it for checking and not for daily student use, and check the rest of the bench against it on a stated interval. That gives a defensible answer to the question an auditor, an examiner or a customer will eventually ask: how do you know this reading is right?
Ask us, item by item, whether a calibration certificate is supplied, what it is traceable to, who issued it and on what date, what the recalibration interval is and what recalibration costs locally. An instrument sold without any certificate is a teaching aid rather than a measuring instrument, which is perfectly acceptable for showing a student what a waveform looks like and not acceptable for a result that leaves the building. Decide which of the twelve items need to be in the first category and which in the second before you order, because it changes the price and the lead time.
A 100 MHz oscilloscope used with a 10 MHz probe is a 10 MHz oscilloscope. Ask what probes are supplied, what bandwidth they are rated at, whether they are switchable between direct and ten-times attenuation, and what a replacement pair costs - probes are the consumable on a student scope and they break at the connector, the tip and the ground lead, in that order. Two habits belong with them. First, probe compensation: a times-ten probe has a trimmer that must be adjusted against the calibrator output, and an uncompensated probe makes a square wave lie to you. Second, and more important for safety, a probe ground lead must never be clipped to the chassis of equipment whose chassis is not isolated from the mains - the result is a short circuit through the scope. Where consumer equipment is being serviced, the bench needs an isolating transformer, which is covered in the consumer electronics workshop range.
Analog or digital, honestly. Both scopes in this listing are analog. An analog scope is a genuinely good teaching instrument: the trace is live, the controls map directly onto what the instrument is doing, and a student learns to think in time and amplitude rather than in menus. But it cannot capture a single event, it cannot measure automatically, and it cannot hand you a screenshot to mark. A digital storage scope does all three, and for a workshop that assesses practical work the saved screen is worth more than it sounds. There is also a supply question: volume manufacture of analog scopes has largely stopped, so before buying one for a ten-year service life, ask about tube and spares availability and the warranty position. If both routes are open to you, a reasonable compromise is one analog scope per workshop for teaching the fundamentals and digital scopes on the student benches.
The frequency counter. Its headline is the maximum frequency, and that is not what determines whether it is any good. The accuracy of a counter is the accuracy of its timebase, quoted in parts per million and specified over a temperature range and an ageing period. Ask for that figure, along with gate times, displayed resolution and input sensitivity. A counter that reads to 1300 MHz with a loose timebase is worse than one reading to 100 MHz with a good one.
The function generator. Two megahertz is ample for teaching, so judge it on the rest: how clean the sine wave is, whether the output is a defined 50 ohms, whether amplitude stays flat across the band, whether there is a DC offset control, and whether a separate logic-level output is provided for clocking digital circuits. A generator without a square or TTL output limits what can be done with digital trainers.
The decade boxes. These look like the simplest items in the range and they are the ones most often disappointing in use. Three figures matter and are rarely quoted: the tolerance of each decade, not of the box as a whole; the residual value with every dial at zero, which on a resistance box is switch and contact resistance and sets the lowest value you can usefully set; and the current or voltage rating, because a resistance box put into a bridge or loading experiment at full supply can be overheated in seconds. For the capacitance and inductance boxes, ask about the frequency range over which the stated value holds, and for the inductance box, its series resistance and self-capacitance.
Count the practical groups in one session, then count the instruments. A measurement workshop needs, per group and as a minimum, a supply, a multimeter and an oscilloscope; the function generator, counter and decade boxes can be shared between groups if the exercises are staggered. Storage matters more here than in other workshops: leads, probes and adaptors disappear and cost more over five years than one of the instruments. Ask us to quote a lead and adaptor set per bench alongside the instruments.
One defect worth knowing before you order. The rheostat in this listing has no product code of its own - it appears at the end of the resistance decade box record, so it will not be found by searching and cannot be ordered by code. Ask for it by name, state the resistance and current rating you need, and have both confirmed on the proforma invoice. One of the two oscilloscope records also names a third-party component manufacturer in the product title; what matters for your purchase is the specification and the spares position, so ask for those rather than relying on the name.
Instrument teaching as a subject rather than instruments as tools is covered by testing and measuring lab trainers, instrumentation trainers and the power instrumentation lab range. The workshops that consume these instruments are the electrical and electronics workshop, the communications workshop and the information technology workshop; the full set is listed under workshop training equipment.
Ask for: calibration certificate, traceability and date, item by item; accuracy or accuracy class for every meter, and basic DC accuracy for the multimeter; probe bandwidth and what a replacement pair costs; timebase stability for the counter; decade tolerance, residual value and rating for each decade box; nominal voltage, frequency and plug pattern; a lead, probe and adaptor list per bench; spares and consumable prices with lead times; and the warranty and service position, including where repair is carried out. For any certification stated here, contact us for the latest copies of the relevant certificates before you tender on it. For a quotation, tell us the destination country, the number of practical groups and the syllabus or tender specification you are working to.
No. Buy one instrument of the type you measure with most often, in practice the bench multimeter, with traceable calibration, keep it for checking rather than daily student use, and check the rest of the bench against it on a stated interval. That gives a defensible answer when an auditor, examiner or customer asks how you know a reading is right. Ask, item by item, what calibration documents are supplied, what they are traceable to, who issued them and when, the recalibration interval and who recalibrates locally. Contact us for the latest copies of the relevant certificates, and decide which items need them before ordering.
Probes matched to the scope, because a 100 MHz oscilloscope used with a 10 MHz probe is a 10 MHz oscilloscope. Ask what probes are supplied, their rated bandwidth, whether they switch between direct and ten-times attenuation, and about replacements, since probes are the consumable and break at the connector, the tip and the ground lead, in that order. Teach compensation: a ten-times probe has a trimmer set against the calibrator output, and an uncompensated probe makes a square wave lie. Never clip a probe ground lead to a chassis that is not isolated from the mains; use an isolating transformer instead.
Both scopes listed (TMW-0005, TMW-0006) are analog, and an analog scope is a genuinely good teaching instrument: the trace is live and the controls map directly onto what the instrument is doing, so students learn to think in time and amplitude rather than menus. But it cannot capture a single event, measure automatically or save a screen to mark, which a digital storage scope can. Volume manufacture of analog scopes has largely stopped, so for a ten-year service life ask about tube and spares availability and the warranty. A sensible compromise is one analog scope per workshop and digital scopes on student benches.
Not by their headline figures. The counter (TMW-0009) is quoted at 1000 or 1300 MHz, but its accuracy is the accuracy of its timebase, given in parts per million over a temperature range and an ageing period; a counter reading to 1300 MHz with a loose timebase is worse than one reading to 100 MHz with a good one. Ask also gate times, resolution and sensitivity. For the 2 MHz function generator (TMW-0008), which is ample for teaching, ask how clean the sine is, whether the output is a defined 50 ohms, whether amplitude stays flat, and whether a logic-level output is provided.
Three figures that are rarely quoted for TMW-0010 to TMW-0012: the tolerance of each decade rather than of the box; the residual value with every dial at zero, which on a resistance box is switch and contact resistance and sets the lowest useful setting; and the current or voltage rating, since a resistance box put across a full supply can overheat in seconds. For the capacitance and inductance boxes, ask the frequency range over which values hold, and the inductance box's series resistance. The rheostat has no code of its own, so ask for it by name with its resistance and current rating.
Count the practical groups in one session, then count instruments. As a minimum each group needs a supply, a multimeter and an oscilloscope; the function generator, counter and decade boxes can be shared if exercises are staggered. For the supplies, TMW-0001 and TMW-0002, ask the voltage and current per output, whether outputs are isolated from each other, how current limiting and short circuits are handled, and whether the bench supply is fixed or variable. Plan storage as well: leads, probes and adaptors disappear and over five years can cost more than an instrument, so ask for a lead and adaptor set per bench.
Ray Export is a manufacturer and exporter of laboratory, scientific and educational equipment based at Plot No. 449, HSIIDC Industrial Area, Saha, Ambala, Haryana 133104, India. Enquiries: [email protected], +91-9817319615.
Written by Palak Mall, Senior Content Writer. Technically reviewed by Arvind Kumar, Lab Equipment Specialist, 12+ years in laboratory and testing instrumentation. Last updated: 17 October 2026.
Specifications for TMW-0001 to TMW-0012, including accuracy class, probe bandwidth, timebase stability and each decade's tolerance, residual value and rating, are confirmed in writing on the quotation. For calibration documents, contact us for the latest copies of the relevant certificates, item by item. No price is quoted on this page. Listing note: the rheostat has no product code of its own and sits at the end of the resistance decade box record, so it cannot be found by search or ordered by code; and one oscilloscope record names a third-party component manufacturer in its product title.
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