Alternatives to the Radio Shack Lab Exerciser

Alternatives to the Radio Shack Lab Exerciser

Availability of the radio Shack 28-280 seems to be a problem. For the price it is the best prefabricated thing on the market. Shown at the right the 28-280 makes both analog and digital circuits easy as possible. the features fit the gaming industry quite nicely. If you've been having trouble getting one, don't be surprised. It literally took me months to round up four of them for our in-house training program.

There are a number of other breadboard setups on the market. Going price is seldom below $100 and can go up as high as $500. For the $50 or $60 it costs the 28-280 is a bargain.

If, however, they are not available to you, all is not lost. All the features of the 28-280 can be picked up in pieces or built on your own. You will probably eventually spend a bit more than what you would have paid for the 28-280, but putting a setup of your own together on a budget of $10 to $20 per month might sound preferrable to you.

Jameco is one, of many, distributors of electronic components. Jameco sells the breadboards themselves starting at less than $6.00. The JE21 (Jameco p/n 20600) shown at the right here has a list price of around $5.25. Price may vary. It is a smaller version of what is built into the 28-280, but it is quite suitable for many lab exercises. Jameco distributes others at various prices and capabilities.

Power may be supplied by batteries. Jameco sells a battery pack that will hold four AA batteries. It is an enclosed box with a power switch built in. Part number 286186 and it shown just to the right here. Most of the experiments are designed to run on 6 Volts. Most of the analog and digital exercises will work fine from 6 Volts. AA batteries are cheap and will not put out enough power to make a mis-wired circuit errupt into smoke and flames.

Other than a power source you will need switch inputs and LED outputs, Potentiometers, 7-segment displays, other power sources, audio amplifiers and a slew of other add-ons. Each of these may be made when you get to these exercises. For the first lessons all you really need is a few square inches (like the 20600 provides), a few simple components and a meter. The meters may be picked up cheap. For your first one don't spend more than $10 to $15. Most digital multimeters in this price range are of suitable quality for the exercises. They are not professional quality, but you will feel better about blowing up your first meter if you only spend $10 on it instead of $150. All that is really needed is found on most meters. DC Volts down to a 200 mV scale, AC Volts, Ohms, DC Current down to a 200 mA scale. A built-in transistor checker is nice, but not required. We'll build one when we first get to transistors.

Likewise I suggest building eight LEDs up on a small board for General Purpose digital outputs. Another circuit board can have an 8-section DIP switch for General Purpose Digital inputs, and a board with four clean switch inputs can be really helpful. Each of these may be built for less than one dollar to a little over two dollars each. Building them on other boards keeps the main breadboard from getting cluttered up with peripheral circuits.

Following are some of the suggested components. Jameco prices are quoted. I suggestyou shop around and compare prices.

1N5225B, Jameco 179004, Zener Diode, 3.0 V, 0.5 watts, $0.033 each if you buy 10 at a time. Yes, that 3 and 1/3 cents apiece.

1N4734A, Jameco 178790, Zener Diode, 5.6 V, 1 W, $0.066 each at a quantity of 10.

1N914, Jameco 36311, Silicon signal diode, $0.022 each @ 10. (= 1N4148)

Q401E3, Jameco 160194, Triac, 400 V, 1 A TO-92, $0.59 ea. Get a few.

2N5064, Jameco 211431, SCR, TO-92, 200 V, 0.8 A, $0.14 ea @ 10.

1N4004, Jameco 35991, Rectifier, 400 V, 1 A, $0.04 ea @ 10.

1N5819, Jameco 177965, Schottky Diode, 40 V, 1 A, $0.10 2 10.

2N3904, Jameco 38359, transistor, NPN, TO-92, 40 V, gain 100 @ 10 mA, $0.075 @ 10

2N3906, Jameco 38375, transistor, PNP, TO-92, 40 V, gain 100 @ 10 mA, $0.05 @ 10

BS170, Jameco 256031, N-MOSFET, TO-92, 60 V, $0.10 @ 10

BS250, Jameco, 256057, P-MOSFET, TO-92, 45 V, $0.23 ea. Get a few.

4N25, Jameco 40985, Optoisolator, $0.18 @ 10

H11AA1, Jameco 18825, Optoisolator, AC input, $0.39 ea. Get a few.

MOC3021, Jameco 95038, Optoisolator, AC output, $0.46 ea. Get a few.

H22A1, Jameco 114104, Slotted Optical Switch, $0.56 ea. Get a few.

LEDs. Pick up an assortment as cheap as you can find them. (Jameco, Radio Shack)

Resistors, assorted, 1/4 w, 5%

Capacitors, assorted, small (<100 uF, <100 V)

10K Ohm trimpot, 3362P-103, Jameco 254094, $0.59 ea.

KRS-3550-WH, Jameco 155256, Pushbutton switch, $0.20 @ 10

206-8, Jameco 38842, 8-section DIP switch, $0.89 ea.

LM555CN, Jameco 27422, Timer, $0.27 ea. Get a few.

8-pin DIP socket

ADC0804LCN, Jameco 10153, 8-bit ADC, $2.49 ea.

DAC0808LCN, Jameco 14947, 8-bit DAC, $1.59 ea.

LM317LZ, Jameco 23552, $0.23 ea

LM317T, Jameco, 23579, $0.45 ea

TL431ILP, Jameco 278248, TO-92, $0.41 ea.

LM2931Z-5.0, Jameco 121048, TO-92, LDO, 5.0 V, $0.39 ea

TL062CP, Jameco 33161, Op Amp, 8-pin DIP, $0.21 ea.

LM324AN, Jameco 212169, Quad Op Amp, 14-pin DIP, $0.22 ea

LM358N, Jameco 23966, Dual Op Amp, 8-pin DIP, $0.20 ea

14-pin socket

LM339AN, Jameco 143888, Quad VC, $0.24 ea.

LM393N, Jameco, 24281, Dual VC, $0.20 ea