A short while back one of our forum members (Riki) was having some troubles building regulator boards, which turned out to be some bad 317 regulators. This got me thinking about building a regulator tester that could easily be used to test one or more of any of the common regs that we use, before soldering it into a circuit, only to find out is has failed. The tester is easy to use and the reg in question just plugs into a socket quick and easily. For testing adjustable regs such as 338 or 317 there is a pot so it can be run through its entire range of voltages. The indicator is an inexpensive offshore 2-wire digital DC voltmeter of the 0.28 variety. They are available in several colors including red, green, yellow etc.
Here is the finished board ready for testing:
Here are tests of a variable reg and a 12 volt fixed reg for examples:
Note in both cases the leading digit "1" does not appear, due to the scanning nature of the indicator. All digits appear fine to the eye, but the camera typically does not get them all in the same frame.
Here is a sample ebay listing for a 2 wire .28 digital indicator. Prices vary of course. Domestic sellers are also available, but at higher prices, but faster deliveries.
Here is the simple circuit:
Cost of a board should not exceed 3 bucks allowing $1 for the indicator, and about $1.50 per board from OSH Park.
The reg receptacles are made easily using an 8-DIP IC socket. Simply cut it down using a side cutter as need to make two inline 3 pin receptacles, and solder them in.
The gerber files are attached below.