Irwin Power Supplies

We offer three different colour cases for the entire range of Irwin Products. They are - Original Irwin Blue (B), Gloss Black (Bk) and Crystal Clear (C). Please specify case colour by using the appropriate suffix.


Irwin Powerbase V8

This is an updated version of the Irwin Powerbase 32. Essentially it is the same as the 32 but has a higher power rotary transformer and a high specification toroid transformer replaces the original chassis transformer. The unit supplies 0-20V smoothed dc and 0-16V ac at 8 amps. Output is continuously variable and protected by a panel mounted thermal cut out. An output limiter is fitted which allows the user to preset the maximum voltage available.

Powerbase V8                                                                                                                           152.25

Powerbase S8

The Powerbase S8 offers 0 to 12V at 8 amps via a relay switching system that provides the voltages in 1V steps. ac and dc are available simultaneously in any combination up to a combined output of 8 amps. Output is protected by a panel mounted thermal cut out. An output limiter is fitted which allows the user to preset the maximum voltage available.

Powerbase S8                                                                                                                        131.25

Powerbase S5

The Powerbase S5 provides ac and dc outputs of 2, 4, 6, 8, 10 or 12V at a maximum combined output of 5A. Output is protected by a panel mounted thermal cut out. An output limiter is fitted which allows the user to preset the maximum voltage available.

Powerbase S5                                                                                                                  103.95

Repair Kit for Irwin Power Supplies

After about 25 years the blue cases become brittle and are prone to cracking. The innards are pretty bomb proof and all that is needed to bring the units back into usable service is a case.  We are offering a repair kit comprising a brand new case (Blue, Black or Clear), three "mushrooms" for the rear to act as a cable tidy, a cable clamp, an alternative cable gland (much easier) and full instructions.  As some people have had difficulty removing the cable clamp, we also sell the special tool to help with this.

Replacement Case (B)                                                                                                       26.25

Replacement Case (Bk)                                                                                                     26.25

Replacement Case (C)                                                                                                       26.25

Cable Clamp Removal tool                                                                                                10.50

Metrel Power Supplies


An extremely well made and rugged continuously variable power supply. Output is 0-33V ac and 0-46V dc. Both can be read from the voltmeter which is connected in parallel to the output. The ammeter indicates the output current drawn, which is up to 6A. In the event of a short circuit the voltage at the terminals is cut off automatically. The power supply also features a soft start feature to protect against start current pulses tripping out the mains fuse. The unit has a built-in C-filter for filtering out the ac component of the dc voltage.

Metrel MA4852                                                           299.00



Specification as above but with one important exception. The MA4853 is fitted with a CLC filter to severely reduce the ac component of the dc. The hum and noise of the dc output is 200mVpp (I=6A) and 30mVpp (I = 1A).

Metrel MA4853                                                           349.00

 IRWIN Heat Pad

A versatile heat pad that allows the user to heat up beakers, conical flasks etc. The unit heats up to about 90 degrees Celcius which is great for heating water, boiling alcohol etc.  Particularly useful where teaching must be performed in a classroom without a gas supply.  The unit is waterproof and splash proof and so may be used where spillage is possible.  Comes complete with 1.5m of silicon cable and 13A mains plug. It is supplied bonded to a heatproof mat to protect benches and tables.  If the children touch it then reflex action will remove their hand before burning can occur - much safer than a Bunsen burner!

Irwin Heat Pad + Heatproof mat                                        20.00

Irwin Low Voltage Heat Pad

A 12 volt version of the above Heat Pad.  Ideally suited to producing a small water bath for biology and chemistry experiments.  May also be used for physics heat experiments and for general heating purposes. May be operated submerged as it is sealed against water ingress.  Requires a 12V, 5A power supply (minimum) to operate. Full instructions on how to calibrate the temperature are supplied.

LV Heat Pad on Heatproof mat                                            20.00                                                       

Irwin WB8 - 8 litre Digital Water Bath

Photo to Follow

Introducing a compact, cost effective water bath for general lab use.  The water bath is based around a deep Gratnell's tray and features a sealed silicone heating element and digital temperature controller. The unit comes complete with an aluminium test tube rack and translucent lid.  Will operate at any selected temperature up to 100 degrees Celcius keeping the water within 1 degree of the selected temperature. Supplied with a fixed 1.5 mains cable and mains plug.  Will operate with amounts of water from 2 to 8 litres.  May be stored in a Gratnell's trolley when not in use.

Irwin WB8 (introductory offer)                                               250.00

Planck's Constant Apparatus

A multipurpose unit that allows the user to easily calculate Planck's constant, to measure the wavelength of coloured light, demonstrate colour light transmission through colour filters and show the diffraction patterns for various wavelengths of coloured light.

Comes complete with a 500l/m diffraction grating, plug-top psu and full instructions.

Planck's Constant                                                                                                             31.50              

Alert - Red and Green Lasers

CLEAPSS have recently cast doubt on our lasers (see below) stating that they are of greater power than 1mW.

We have checked this and found it to be true. However we have also tested for infra-red content, which is the danger to sight with lasers, and found that there is no infra-red content in the light. The boss regularly demonstrates their safety by shining the lasers in his eyes - with no ill effects. Therefore we are continuing to sell the lasers as safe for use in schools.

Green Laser Ray Box

* No blackout required

* No powerpacks to move from lab to lab

* No risk of burning from hot lamps

* No replacement lamps to buy - lasers last at least 5,000 hours

A battery operated green laser raybox that may be used in classrooms without blackout facilities. The green laser light has a wavelength of 532nm, which is extremely close to the peak response of the human eye. This means that although the same power as our red laser rayboxes, the green laser light appears many times brighter. All our rayboxes contain Class 2 laser elements - Class 2 is the only type of laser approved for use in schools.

The green laser raybox produces a bright green line that may be easily used for reflection, refraction and diffraction experiments.  The unit is powered by two AAA cells (not supplied - Alkaline Manganese type are recommended) but can easily be converted for plugtop power supply operation. Click here for details.


Battery Operated

                  Green Laser Ray Box                                 37.80

                  Green Laser Ray Box (5 or more)            28.35           

Battery/mains Operated

                  Green Laser Ray Box + PSU                      46.20

                  Green Laser Ray Box + PSU (5 or more) 35.20            


Red Laser Ray Box


A red (650nm) version of the above laser ray box. Has all the advantages of the above except that the beam is not as bright. May be easily converted to produce a spot for diffraction demonstrations etc. Uses two AAA alkaline cells or may readily be converted for plug top PSU use.

Battery Operated

Red Laser Ray box                                         26.25                                     

Red Laser Ray Box (5 or more)                   21.00

Battery/mains Operated

Red Laser Ray Box + PSU                           34.65

Red Laser Ray Box + PSU (5 or more)     28.20

Red and Green Demonstration Lasers

The above laser ray boxes are also available as demonstration lasers, which project a bright spot of laser light for use in diffraction and holography experiments.  The price of all variants is the same as for the equivalent laser ray box.


Demonstration Colour Mixing Apparatus


The kit is designed  to demonstrate primary and secondary colour mixing.

The kit comprises, essentially, a scaled up version of our small colour mixing apparatus.   A robust, upright case contains three, high power, accurately colour matched leds, each of which has infinitely adjustable brightness. Also supplied is a large, free standing, primary colour shadow mask, a hand held secondary colour mask and a 12V plug top power supply. 

The system allows the teacher to project large primary and secondary colour mixing disks onto any vertical surface and to adjust the colour saturation to mix virtually any colour (How do you produce brown?).  Unlike other systems the purity of the resulting white is outstanding.

The unit is extremely easy to use, is easily transportable and comes with full instructions. The only other requirements are a white wall and a darkened/blacked out room.

The system may be used to demonstrate both secondary and primary colour mixing, colour shadows and colour reflection/absorption.

Demonstration Colour Mixing Apparatus with plug top PSU                                                66.15

Mini National Grid Simulator

The system comprises two printed circuit boards fitted with step up/step down transformers, 4mm low voltage connectors, "high voltage" jack sockets, 2.5V MES lamps and a set of "HT" leads.  The system is classified as Safety Electrical Low Voltage - in other words it does not generate harmful voltages and is safe for pupil use.  The system allows the pupil to investigate the effect of stepping up the voltage to transmit power, as used in the National Grid.  All it requires are two, 4mm plugged leads and a 2V ac power source.  Comes complete with a 1m long set of transmission cables and full instructions.

Mini National Grid Simulator                                                                                          51.45      

1.5-30V @ 1A dc Regulated Power Supply with digital metering

The unit is a compact, lightweight bench-top power supply in a stylish enclosure. Designed as an affordable yet highly functional piece of lab equipment, connection to the power supply is via standard pitch (19mm) 4mm sockets. The continuously adjustable output voltage can be set to within 0.1V, using the adjustment dial on the front of the unit and the current may be read to a resolution of 0.01A. Overvoltage/current and short circuit protection.  A large backlit LCD displays the output voltage and the current being drawn. The PSU measures only 135 x 140 x 53mm (5.3" x 5.5" x 2.1") and can be tilted to adjust the viewing angle of the display.

1.5-30V, 1A PSU                                                                              72.45                                                                                                                                                                 

BERT - Battery Electrical Resistance Tester

A self contained resource to aid understanding of electrical resistance


An extremely versatile kit for teaching about electrical resistance and resistivity.  Draw a pencil line across BERT, study the LED brightness. Then make the line wider. What happens? Draw a second line in parallel. Change the length of the lines. Change the thickness (height) of the line. Can be used to compare conductors and insulators including the entire class! Test the conductivity of liquids.

Comes with PP3 battery, crocodile clip lead, eraser, pencil and comprehensive instructions.

Have a look at the instructions and suggested experiments by clicking here.

BERT                                                                                    15.75