Category Archives: Anything

This web page and lots of other small web pages are powered from recycled computers. The hardware is very old… Yesterday, very old Seagate SCSI disk drive failed… This was very sad news, as the backup of the disk is … Continue reading →

PWM transformer are wounded like ordinary transformers. But there are some important differences. As the working frequency of the transformer are much higher than ordinary line transformer, the windings contains much less turns. Also, skin effect is introduced. Also there … Continue reading →

Ferrite core transformers are used in high frequency power supply. The main core parameters are core material and area of core cross-section. Area can be calculated using regular geometric formulas. The problem is to determine core material- they all look … Continue reading →

The main component of PSU is TOPSwitch-GX chip. There are produced whole line of these chips: TOP242 (weakest), TOP243, TOP244, TOP245 (used in this design), TOP246, TOP247, TOP248, TOP249 and TOP250 (Most powerful- 10A switch, up to 290W output power). … Continue reading →

This is simple, quite powerful and economical power supply. You don’t need to switch it off- when load is off, the psu draws on fraction of Wat of the power. (80 mW @ 110 VAC, 160 mW @ 230 VAC). … Continue reading →

To start old Optrex DMC50264N LCD module you need to get +24V LCD bias voltage? Where to get it if you have only low voltage 3 … 5V? As LCD module drains very low current, it is possible to build … Continue reading →

One of the popular programs for PCB tracing and circuit diagram drawing is Eagle from Cadsoft. The software is available for Windows, Linux and Mac operating systems. Freeware version of software has some limitations: The usable board area is limited … Continue reading →

Got some bad security video cameras for recycling. Few color ones made by Philips, two Sanyo and others KC-263C and KC-383C. It is mid and high resolution black and white CCIR video cameras. Security cameras’ bodies and some generic brown … Continue reading →

Connect pulse generator from older post to your audio amplifier. Set volume to something in the middle. Connect oscilloscope to the output of the amp with dummy load. You will not see ideal square signal in the output, but all … Continue reading →

For further audio amp analyze we need square waveform generator. I can use my generator, but we can build one using very common TTL chips. We can use any 74XXXX chip which can be combined to “NOT” logic element. Most … Continue reading →