Blog Archives
Posted on 13 Feb 2008
This is a very cool project for all hobbyists.It is a PIC16C71 based 4-digit LED frequency-counter & Volt-meter. Some hard to find parts used in the previous version, which are out of production for some time, has been omitted. A rather early PIC16C71 has also been replaced by 28-pin device PIC16F876. The later is capable of driving 4 digit LED display in multiplexed mode while measuring frequency, power supply voltage as well as handle two analog inputs to display SWR/PWR signal strength in a bargraph manner. There is no need for external LED display driver chip as well as external data EEPROM since it is already implemented in PIC16F876.[more]
Posted on 04 Feb 2008
This PIC-based Ultrasonic Range Meter,the heart of project is PIC16F873,The ultrasonic signal which was received with the reception sensor is amplified by 1000 times(60dB) of voltage with the operational amplifier with two stages. It is 100 times at the first stage (40dB) and 10 times (20dB) at the next stage.As for the dB (decibel), refer to “Logarithm Table”.Generally, the positive and the negative power supply are used for the operational amplifier. The circuit this time works with the single power supply of +9 V. [more]
Posted on 31 Jan 2008
This a wide rang input DC-DC converter that is designed to accept a range of input voltages that are present in a car’s electrical system which not alway equal 13.8V, and provide a regulated 12v output. Nominally, the battery voltage is about 13.8v, but when the engine is being started, the voltage can often droop down to 6 or 7 volts for a short time, and peaks can be present somewhat above the nominal voltage as well. Because the input voltage can be either above or below the desired output of 12v, the converter needed to be a buck-boost configuration.[more]
Posted on 30 Jan 2008
Read this article if you have a LCD monitor that either does not turn on or turns on and off randomly. There might even be a high pitch squeal when it is on.[more]
Posted on 28 Jan 2008
This is a bench power supply with regulated DC outputs -12V, -15V, +5V, +12V, +15V, and variable and one +35VDC unregulated output. This bench supply almost exclusively upon Andrew Kilpatrick’s design. [more]
