Monthly Archives: October 2011

LED or Lamp Pulsar Circuit

Astonishing effect 4.5V supplyThis circuit operates a LED in pulsing mode, i.e. the LED goes from off state, lights up gradually, then dims gradually, etc. This operation mode is obtained by a triangular wave generator formed by two op-amps contained in a very cheap 8 pin DIL case IC. Q1 ensures […]

October 31st, 2011|Lights and Leds|0 Comments

Simple Hybrid Audio Amplifier

The debate still goes on as to which are better, valves or transistors. We don’t intend to get involved in that argument here. But if you can’t make your mind up, you should try out this simple amplifier. This amplifier uses a valve as a pre-amplifier and a MOSFET in the output stage. The strong […]

October 31st, 2011|Amplifier|0 Comments

IrDA Interface

Many modern motherboards are equipped with an infrared data interface compliant with the IrDA standard, but this interface not very often used. However, it is not difficult to build a data transmission module and connect it to the corresponding header. As can readily be seen from the schematic diagram, this doesn’t […]

October 31st, 2011|Computer|0 Comments

Linear RF Power Meter

The National Semiconductor LMV225 is a linear RF power meter IC in an SMD package. It can be used over the frequency range of 450 MHz to 2000 MHz and requires only four external components. The input coupling capacitor isolates the DC voltage of the IC from the input […]

October 31st, 2011|Vumeters|0 Comments

ESR & Low Resistance Test Meter

As electrolytic capacitors age, their internal resistance, also known as “equivalent series resistance” (ESR), gradually increases. This can eventually lead to equipment failure. Using this design, you can measure the ESR of suspect capacitors as well as other small resistances. Basically, the circuit generates a low-voltage 100kHz […]

October 31st, 2011|Vumeters|0 Comments