An alcohol detector is a sensitive device which is able to detect the presence of alcohol molecules or any similar volatile inflammable element in the air and convert it into equivalent level of electrical output. The simple alcohol detector circuit discussed here will accurately sense the emanation of alcohol gas from a selected source, such […]
Meters and Testers
4 Simple VU Meter Circuits Explained
In this post I have explained how to build 4 interesting VU meter circuits, using LEDs and using a moving coil meter. What is a VU Meter VU meter or a volume unit meter circuit is a device used for indicating the music volume output from an amplifier or a loudspeaker system. It may be […]
Simple Transistor Diode Tester Meter Circuit
In this post I have explained how to make a simple yet efficient transistor/diode tester circuit, that will not only test the quality of a BJT, but will also help to identify whether it is is an NPN or a PNP. The circuit was designed and contributed by Mr. Henry Bowman. Circuit Operation Referring to […]
Simple MOSFET Tester and Sorter Circuit
This simple MOSFET tester does a quick job of testing both enhanced mode type N and P-channel mosfets. It checks for shorts between gate, drain and source. Designed By: Henry Bowman It also distinguishes between N and P-channel mosfets. Once the connections are correctly made to the mosfet, all testing is done without reversing connections. […]
Circuit Tester Probe – PCB Fault-Finder
This simple circuit tester probe can be used for detecting short circuits, abnormal resistance conditions, continuity breaks etc inside an assembled circuit board or a PCB. The indication will be through an audible buzzer sound or an LED illumination. The described designs are all extremely safe to use even with PCBs that may have highly […]
Remote Control Infrared Tester Circuit
We all use remote control handsets for controlling various household devices such as TV, AC, Music systems, curtains etc, and sometimes we seem to have problems with these devices, or even a newly purchased remote controller unit occasionally seem to malfunction, and identifying the issue becomes quite difficult for us. This simple 2 transistor infrared […]