Schematic Diagrams

Useful schematic and wiring diagrams. ✔ ✔ Enjoy electronic circuits, let your idea comes to hardware


Infra-red Light Barrier Using 555

This is a short-range light barrier for use as an intruder alarm in doorposts, etc. The 555 in the transmitter (Figure 1) oscillates at about 4.5 kHz, supplying pulses with a duty cycle of about 13% to keep power consumption within reason. Just about any infra-red LED (also called IRED) may be used. Suggested, commonly […]

, , ,

Simple Function Generator

Simple triangle-wave generators have a weakness in that the waveform of their output signal normally cannot be modified. The circuit presented here makes it possible to smoothly alter the waveform of a linearly rising and steeply trailing saw-tooth signal through a symmetrical triangle-wave to a slowly trailing, steeply rising linear sawtooth. The wanted waveform may […]

, ,

PWM Modulator

If you ever thought of experimenting with pulse-width modulation, this circuit should get you started nicely. We’ve kept simplicity in mind and used a dual 555 timer, making the circuit a piece of cake. We have even designed a small PCB for this, so building it shouldn’t be a problem at all. This certainly isn’t […]

, ,

Mini Lithium Torch

This mini pocket torch combines the advantages of Lithium button cells with a super-bright white LED. The lithium cells are small, have a long shelf life and have very little self-discharge. The LED has very high efficiency, an extremely long life expectancy and a modest current consumption (20mA). In combination this results in an exceptionally […]

, ,

Pulse Width (PWM) Controller Circuit

A LM3900 quad operational amplifier can be used to build a pulse width (PWM) controller. The LM3900 was chosen because it only need single supply voltage of 4 to 30 V. This circuit can give 100 percent pulse-width control.  A1 op-amp forms a 1 kHz oscillator, generating a square wave oscillator for the basic oscillation. […]

, ,

Small Package Digital PWM Controllers

Small Package Digital PWM Controllers International Rectifier, IR®, a world leader in power management technology, introduced its highly versatile family of CHiL digital PWM controllers that dramatically shrinks footprint and improves efficiency in a variety of mid-range to high-end and extreme server, desktop, and computing applications. IR’s six new devices meet Intel VR12 and VR12.5 […]

, ,

PWM Control Speed Motor 12V By TL494

This is circuit PWM Control Speed Motor 12V with IC TL494 I See from Idea Circuit by joe (aircraftdesigner) Good Elecronics user. Thank you very much. detail – For Control speed motor 12V max 15A. – R6 Control speed motor. – Driver Motor by Mosfet IRFZ48. – Control at Frequency 100HZ – Adjust PWM duty […]


PWM Motor Speed Controller – DC Light Dimmer by IC LM324

A pulse width modulator (PWM) is a device that may be used as an efficient light dimmer or DC motor speed controller. The circuit described here is for a general purpose device that can control DC devices which draw up to a few amps of current. The circuit may be used in either 12 or […]


PWM 12V DC motor speed regulator

Reverse engineered circuit diagram of a PWM motor speed regulator out of an oral irrigator water pump. This circuit works quite well, keeping the speed of the small PM motor fairly constant regardless of load. No transistor heatsink is required since this is a switching regulator. The efficiency under high load would be a improved […]


PWM D.C. motor drive Low loss speed control By 4093

This circuit is a very compact switching regulator for small DC motors. I use it for my small printed circuit board drill (18 Volt, 1.5 Amp), but it is suitable for many other applications (e.g. 12V DC halogen dimmer). Circuit description R1, R2, C1, D1, D2 and schmitt trigger IC1B build a 1kHz oscillator with […]


Previous Posts