It is an irreplaceable tool for troubleshooting and repairing electronic equipment by determining performance and health of electrolytic capacitors. It also analyzes transistor's characteristics such as voltage and gain. This small supply is user friendly and fits nicely on my cluttered bench.ĮSR Meter / Capacitance / Inductance / Transistor Tester KitĮSR Meter kit is an amazing multimeter that measures ESR values, capacitance (100pF - 20,000uF), inductance, resistance (0.1 Ohm - 20 MOhm), tests many different types of transistors such as NPN, PNP, FETs, MOSFETs, Thyristors, SCRs, Triacs and many types of diodes. With adequate input the LM338 makes a fabulous variable power supply. The diodes steer the current around the regulator and into ground, thereby protecting it from damage. Since the current spike may be many amps, the regulator may fail. Without the diodes, if this happens, the capacitors will dump their charge back through the regulator. Also the output of station supply may be shorted if some other device fails. This is a distinct possibility if using jumpers to attach it to the power supply. Diodes are included to protect the regulator from damage in case the input is accidentally shorted to ground.
I chose one that illustrated variable output and included protection diodes. LM338's Data Sheet has several very helpful application notes and circuits. It began as a variable power supply based on an LM338 5A voltage regulator and external power adapter.
After many years of employing this ugly and clumsy bench power supply, I decided it was time to build something better, smaller and nice looking.