14 June 2009

Prototype Boards for DIP Chips (op-amps)

There are several printed circuit board (PCB) manufactures who cater to hobbyists by offering small quantity orders of PCBs. Some of the larger manufacturers offer free PCB design software that makes it very simple to come up with your own PCB designs. This is all great until you see the price estimate for that pair of simple boards can be in the order of $50 to $100US. Well, when I am spending that much money on parts it is generally for vacuum tubes, an enclosure or perhaps a transformer - a simple PCB, no thanks! Fortunately for simple circuits a prototype board (protoboard) will often suffice and they are generally inexpensive and commonly available. This post examines some of the low cost protoboards that are available for use with an integrated circuit (IC) that comes in a dual in-line package (DIP) - such as an operational amplifier (op-amp).

The noted costs are from 15 June 2009
Dual General-Purpose IC PC Board - Radio Shack 276-159 - ($2.49US)
This general purpose board is perforated and can be split into two pieces. Each piece will accept up to a DIP20 package or a couple of smaller DIPs can be fit on a board. The overall dimensions
Radio Shack 276-159 Protoboardare 1-3/4" x 3-3/8" and when split apart each board measures 1-3/4" x 1-3/4".

The board is constructed from phenolic which is generally flimsy, but given the small size of the boards that is not an issue. Be careful when mounting using the screw holes as it is easy to break a corner off the board. The board is easy to work with but the small size will limit it to small projects. One problem with the board is that the solder pads are fairly thin and as a result with rarely survive desoldering and re-soldering if you need to make changes to the circuit.

What is nice about the boards is that they are often locally available and their low cost. The boards are available from Radio Shack in the US for $2.49US:
Here are a couple of DIY Audio Projects that use the boards:

Multi-Purpose PC Board - Radio Shack 276-150 - ($1.99US / $4.99CDN / $2.96AU)
The Radio Shack 276-150 is a popular multi-purpose protoboard. The overall dimensions of the protoboard are 1-7/8" x 2-7/8" (48 x 73 mm). There are 417 holes on the board and up to a DIP50 Radio Shack 276-150 Protoboardpackage or a few smaller ones can be fit on the board. Two traces run down the center of the board which can be used for grounding or power rails.

Like the previous Radio Shack protoboard it is also constructed from phenolic. On the 276-150 board the mounting screws are very close to the edge and it is very easy to break a corner off. Also, the solder pads are thin and will lift off the board if too much heat is applied. The boards are a good size and very easy to work with. There is plenty of space to get three DIP8 op-amps on a board.

These boards are very common and available in the US ($1.99US) , Canada ($4.99CDN) and Australia ($2.69AU):
DIY Audio Projects that use these boards:

D-4 Prototype Board - audioXpress PCBD-4 - ($4US)
Darren of DH Labs was kind enough to send us a sample of his prototype board design. The board measures about 2-1/4" x 3-1/4" and can hold a DIP50 package with space DH Labs D-4 Prototype Boardleft over. A ground trace runs down the center of the board and there are also two power supply traces on either side. The board is constructed from fiberglass and the pads are tinned.

With
the ground and power traces the D-4 Prototype Board is ideal for use with op-amps. There is plenty of room to fit up to four DIP8 packages on the board. The fiberglass construction and distance of the mounting screws from the edge make it unlikely that the corners will break off when mounting. The soldering pads are fairly durable and will survive desoldering and re-soldering if you need to make circuit changes. Considering the cost of the 276-150 boards in Canada, the switch to the D-4 boards is an easy one for me.

The D-4 Prototype Board is available online through audioXpress ($4US):
The photo below is a DIY Phono Preamplifier that Darren put together using the board.

DH Labs D-4 Prototype Board
Please let us know if you have a favorite protoboard that you use with op-amps.


What's Playing: Rebecca Pidgeon - Grandmother

1 comment:

  1. Use solder posts and get around the problem of traces lifting after a few solder/re-solder.
    With posts you can solder once, mess around for ever...

    ReplyDelete

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