Free Circuit Diagram

LM56 is a monolithic  thermostat designed for simple temperature control. The chip has two programmable threshold that can be used to drive a fan and or alarm.  Here is the schematic diagram of the fan control circuit:

The circuit will turn on the fan when the temperature rise above 50 Celsius degree, and this threshold is [...]

Using only transistors as the active components, we can build a simple and low cost TTL-to-RS232 level converter. It uses only two transistors as the active components. Here is the schematic diagram of the converter:

You can use any small signal transistor for this RS232 converter circuit. You can see the collector of Q1 transistor is [...]

Light dimmer circuit is used to control the lamp for arbitrary brightness. This dimmer circuit work for incandescent lamp, not a fluorescent one.  The dimmer circuit here work for both 110V and 220V AC.  Here is the schematic diagram of the circuit:

Dimmer Wiring Diagram
The dimmer circuit is wired in series with the lamp, you can [...]

Many new computers now only has USB port, and this serial to USB adapter might be the only help for old devices that provides only RS232/COM Port. This serial adapter uses FT232 USB-RS232  converter IC from FTDI (Future Technology Devices International).  The main features of this USB serial adapter chip are:

384 byte receive buffer / [...]

RS485 interface gives some more benefits compared to RS232: simplicity and the robustness for long distance transfer. RS485 is simpler because it uses only two wire (or a single pair) to carry out the data in bidirectional manner, using RS232, we need 3 wires at minimum to carry the data bidirectionally. RS485 cable length can [...]

Using a standard fluorescent tube lamp (TL), you can make your own disco light, similar to a stroboscope light. You can even use a half-broken lamp, which one side of the heating filaments has broken. This circuit use only one side heating filament inside the tube. Look at the circuit’s schematic below.

Please be aware that [...]