Power Supply


13V/2A PSU For Handheld Rigs

This compact 13-V/2-A power supply for ham radio rigs and other VHF/UHF portable PMRs is based on the STR2012/13 voltage regulator IC from Sanken Electric Co. Many power supplies for handheld amateur radio rigs are based on the LM317, LM350 or even the good old LM723. Unfortunately, these regulators are invariably associated with a fair […]


Rugged PSU For Ham Radio Transceivers

This rugged power supply is based on the popular LM338 3-pin voltage regulator. The LM338 is capable of supplying 5 A over an output voltage range of 1.2 V to 32 V with all standard protections like overload, thermal shutdown, over-current, internal limit, etc., built in. In this power supply, some extra protections have been […]


Upgrade Your USB Hub

Problems can arise with USB hubs that are powered from a PC when gadgets plugged into them draw too much current. This is often the case with devices fitted with USB cables that are too long or too thin, causing voltage drop. There’s no need to scrap your old USB hub, however, if you upgrade […]


Ni-MH Ni-Cd Adjustable Constant Current Charger

Ni-Cd Ni-MH Adjustable Constant Current Battery Charger Circuit This is a Adjustable Constant Current Ni-MH or Ni-Cd battery charger circuit. It can be used to get a constant current power supply. Here is the schematic diagram of the circuit: PARTS LIST R1 100Ω VR1 500Ω Preset C1 0.1µF C2 0.01µF D1 1N4001 Q1 BC140 IC1 LM317 […]


LM317 Calculator

LM317 Calculator or LM317 Toolkit Software Program to calculate the resistance at a LM317 / LM117. LM317 toolkit software is completely free, fully functional and easy to use. It runs under Microsoft Windows NT, 2000, XP and Vista. Download


Power Guard

Under and Over Voltage Protector A few circuits on under/over voltage protection have appeared recently in EFY. But this circuit is simple, very easy to construct and inexpensive. It can be added to existing stabilisers, in which case DC power supply can be taken from the original stabiliser circuit and only a few additional components, […]


HV2405E transformerless stabilizer

Using HV2405E chip, manufactured by Harris, along with a few external components connected like in this circuit diagram can be achieved a voltage stabilizer without a voltage transformer. Using HV2405E chip can get a 5 + 24V stabilized voltage directly from the mains AC 100 260V.Peak output current of stabilizer is 50 mA. Integrated circuit […]


DC-DC Multi-Chip Module Family

DC-DC Multi-Chip Module Family New energy standards, combined with new system specifications for blade servers, high performance notebooks, gaming consoles and POL modules, are driving the requirements for better efficiency, higher current, higher switching frequency and increased power density. To meet these industry trends, Fairchild Semiconductor (NYSE: FCS) has developed the FDMF68xx Gen III DrMOS […]


80~120 W Medical Power Supplies

80~120 W Medical Power Supplies CUI Inc announced a further expansion to their VMS medical open frame power supply portfolio with the release of three new series ranging from 80 W to 120 W. The VMS series is designed to be used in a wide variety of medical and dental applications, carrying UL/cUL and TUV […]


1987 Audi 4000S Main Fuse box Diagram

1987 Audi 4000S Main Fuse box Diagram 1987 Audi 4000S Main Fuse box Map Fuse Panel Layout Diagram Parts: upshift relay, load reduction, horn relay, auto trans relay, intermitten wiper relay, fuel pump, license plate light, interior light, air conditioner, glove compartment light, heater control ilumination.cigar lighter, power seat, control unit, windshield wiper, rear window […]