LM317 adjustable current source/regulator A linearly-adjustable current source based on the LM317 regulator, useful for things like laser diodes
Linear power-supply potentiometer feedback Ensuring a linear response and protection against loss of wiper contact
Modifying a power supply for variable voltage Converting a 12V fixed supply into an adjustable 5-15V supply
SSR relay switched mains socket A twin-gang mains socket with an inbuilt solid-state relay
Current-fed inverter advantages An overview of current-fed inverters and why they're better (in my opinion) for resonant loads like induction heaters
Celtic/Pictish circuit board drinks coasters Some really cool drinks coasters made using normal PCB processes
Gate drive transformer testing Making and testing toroidal gate drive transformers
Oscilloscope probe contact tips Making a low-inductance connection to a probe tip
Planetary mutiturn potentiometer A rather strange multiturn potentiometer which uses a planetary reduction mechanism
Old TV tube neck Deflection assembly from an old TV tube neck. Found chucked in the bushes...
Inductor design: energy-storage inductors Some practical steps for designing an energy-storage inductor (e.g. flyback, buck, boost etc)
Brushless motor driver Using a fan driver IC to run some disk drive motors
Mitutoyo SPC Digimatic interface An analogue readout unit for my digital indicator
High-current shunt resistor Making a 100µΩ current-sense resistor from some aluminium bar
RMS and average values of waveforms Derivation for sinewave, half- and full-wave rectified waveforms
Desoldering using a custom "iron" A big lump of brass works well for desoldering multi-pin components
IC decapping Decapping a USB isolator chip
Laser wire stripping Quick way to strip ribbon cable
Laser-cut transformer bobbin Bobbin made from laser-cut 3mm hardboard using finger joints
Resonant charging equations Charge time, peak current, peak inductor energy
Salvaging ferrite cores Removing the cores from SMPS transformers by heating in an oven
USB connector panel insulator A little plastic part which provides electrical insulation and mechanical support for a USB connector
Geiger-Müller tube detector circuit Simple circuit to power a G-M tube
Desoldering SOIC device Removing an SOIC chip using a wire under the pins to pull them away from the board
Pick-and-place Turning my CNC router into a pick-and-place machine
EasyPIC5 ICSP connector and programming jig Adding a pin header to the EasyPIC5 board, plus a progrmaming jig using pogo pins.
Making PCBs My own experiences with making PCBs
Read-modify-write problem Be careful when using tri-state PIC outputs!
Flyback HV supply Some photos of my old high voltage supply
High-value resistor mixture Using a mixture of Aquadag and PVA glue to make high-value resistors
High-speed photodiode Detector using a BPX65 photodiode
Load resistance on PIC's programming pin If a load resistance is present between the MCLR/VPP pin and ground, programming may not work correctly
Fixing a transformer thermal cutout Repairing the transformer in a small desk lamp
Improving ADC resolution by adding noise Deliberately adding noise to an analog signal can improve the resolution achievable
PCB via size test Checking to see how small a via I can make with home etching
Small variac transformers Two small variacs I picked up a while ago - one has an isolated low-voltage secondary, which is a bit unusual.
Large Brandenburg flyback transformer A huge flyback, unfortunately with a cracked winding
Series HV trigger Simple circuit for series triggering of spark gaps, arc lamps etc.
Inductor properties A quick look at how inductor properties (inductance and saturation current) vary with turns and air gap
High-voltage diode stack A potted stack of UF4007 diodes to make a 48kV dual diode
Hot air gun circuit and operation The insides of a cheap Clarke hot air gun
Inductor tester Simple circuit for measuring the saturation current of inductors
Wide-range adjustable pulse generator A circuit to produce pulses anywhere from 200ns to 500ms
Modifying a rotary switch Converting a 4-pole 3-way switch into a 1-pole 12-way version
Film capacitor dissection Removing the ends of a film capacitor to expose the metallising, and then soldering directly to it. Idea for better cooling of the capacitor.
Using an external coil with an induction cooker Winding a coil to fool an induction cooker into thinking it's running its original coil
Resistor colour code chart High-resolution chart of resistor colour codes
1000x capacitive high voltage probe A high voltage oscilloscope probe suitable for measuring fast HV pulses
Removing ground/earth from site transformer This mod allows a site transformer to be used as an isolation transformer with a 110V output.
Triggered spark gap A triggered spark gap using stock hardware
Faulty PCB pin header connectors Not all 0.1" PCB pin header connectors are created equal. A particular intermittent fault was traced to bad connectors.
Bayonet bulb plug adapter Plug to make electrical connection to a light socket
Large resistor model Painted wooden model of a ¼W resistor
TV CRT Tube Socket Socket for TV CRT necks
ICSP adapter for EasyPIC5 Making an adapter cable to allow PICs to be programmed externally
Potentiometer end-stop modification Altering a cheap carbon potentiometer to obtain smooth adjustment at the end of the wiper travel
Making a current-sense resistor How to make a low-ohmic sense resistor using a short piece of resistance wire
40-400V, 20W power supply General-purpose high-voltage power supply for experimenting with Nixie tubes and the like
Surface mount adapter boards Allows SMD devices to be used on a 0.1"-pitch breadboard
Spark radiation detector Spark detector for α particles
Power ultrasonic driver Inverter power supply for a 28kHz ultrasonic tank transducer
High-voltage trigger and capacitor dumper This arrangement was originally designed as an attempt at pulse arc welding, but is useful where a high-voltage, high-frequency trigger pulse is required.
TIG welder with HF start This is not my work, but is a backup of a page I found on another site. It describes the construction of a 180A TIG welder with high-frequency start.
Planté rheostatic machine A completely mechanical means of charging a string of capacitors in parallel and discharging them in series to obtain increased voltages
New 3V camera supply A better 3V supply for my digital camera, this time built in an ATX supply case.
Double-sided exposure alignment jig A useful jig for exposing double-sided things, such as for PCBs or photochemical etching.
Large IC model A 10x scale wooden model of a 555 timer IC
Excellon to G-code converter Program to convert Excellon drill files from Eagle to G-code suitable for running a CNC machine. Also performs geometric transformations to correct for distortion in the board.
Digital Kirlian photography Using a digital camera to take Kirlian photographs.
Nixie tube counter Simple counter circuit to drive a Russian IN-8 nixie counter tube using a PIC. Also interfaces to a telephone rotary dial.
LED on conductive glass A surface-mount LED mounted on a piece of conductive glass.
Laser-cut solder stencil Trial of making a solder paste stencil using transparency film cut with a CO2 laser.
Dual AA battery eliminator If, like me, you have a little digital camera which runs from two AA batteries, then you probably will be fed up with using a lot of batteries when you're taking pictures or videos around the house. This little circuit is a simple 3V adjustable regulator which runs from a 5V supply. I made the adaptor to fit a Nikon L2 camera, but it should work with anything.
PowerPAD™/MSOP-8 heatsink Small copper-foil heatsink for PowerPAD™ IC packages to allow hand soldering
Surface mount component soldering arm Useful tool for holding surface mount components in place whilst soldering
PCB drilling viewer Gadget to drill PCB boards by optically aligning the underside of the board with the drill axis
Induction cooker Brief investigation of the waveforms in a 2kW induction cooker.