This project is an addon to the Nedap Switching PS to gives 0-25A variable constant current output, at maximum voltage of 4V. The current value can set and read by a digital meter before the actual circuit current is flowing.
A battery/walmart powered 2.5V reference for checking DVMs and multimeters. The 12V input is stabilised via 78L05 and thento a LM336-2.5V bandgap reference, fitted with ambient temperature compensation.
An invaluable tool in testing windings and flyback transformers for short turns. This is a popular project that is openly available on the internet. I have added an integral testing switch and facilities so that the function of the tester can be verified via a good coil and a bad coil(a good coil with a one-turn short).
This meter use 100KHz low voltage AC supply to check for the voltage drop across an electrolytic capacitor for its internal impedance. Capacitors with correct capacitance often shown to be bad using the meter. This meter can also speed up the checking of switch mode power supply filtering section.
This project is about a 13.8V 16A linear voltage regulator that I designed and built for my radio transmitter. The actual building of power supply with output more than a few amperes gets complicated because there are voltage drops on the connecting wires. This is what the circuit diagram cannot tell you. Great care must be taken in order that the power supply performs as designed. The component parts used were from previous surplus equipment. The performance of power supply is the best I have ever built.
A battery charger that won't even power on if the output leads are not connected to the correct polarity of the target battery. After the charging is finished, the charger turns off itself.
The charger is built by modifying a PC-XT computer power supply to give 14.4V at about 10A output.
An invaluable tool in testing all projects which require AC power supply. Best for testing transformers, current transformers and powering up appliances after repair. This project explains how on/off switching and protection can be added to make the variac more versatile in daily use.
This enable AC supply to be safely connected to the projects during testing and troubleshooting stages. Features includes a 10-turn coil in series with the live connection so that current can be easily measured using a clip-on ammeter.
Using an UV tube and a couple of capacitors and resistors, this apparatus enable several eproms to be erased within 20 minutes.
This voltage source provides a stable and adjustable voltage over wide ranges. The stable ouput voltage can be use for checking and setting the gain of operational amplifiers and testing trip points setting.
Instead of using selector switch with fixed resistors for setting output voltage, a 10-turn variable resistor is used and a 3-1/2 digit DVM module is fitted to provide continuous monitoring of the output voltage.
This card contains 80C32 CPU, battery backup SRAM, connection for LCD and a realtime clock chip but was only sold for £2.0 by GreenWeld UK. Unfortunately, all were sold out now. This make a very interesting project, seen here with the addition of a serial port and printer port.
Mounting LCD modules on "L" shaped plexiglass enable easier reading and more convenience during prototyping.
Coming soon.....
