Friday, December 12, 2014
Dual zone alarm schematic
This brilliant circuit shows a two-zone alarm - with automatic exit, entry and siren cut-off timers.It can be triggered by the usual types of normally-closed input devices - such as magnetic reed contacts - foil tape - PIRs etc.
The circuit will work at anything from 9 to 15-volts. All you need do is select a siren, buzzer and relay to suit the voltage you want to use.
Simple DC DC Converter
This schematic shows you how to build a dc-dc schematic.Here's a DC to DC circuit put together just from parts found on the test-bench. All it took was two transistors, two resistors, an audio transformer, a bridge and two caps. It may not be the ultimate in performance, but it does work.
The key to how it works is the transformer. As you can see, two transistors drive the transformer primary with the base drive for each coming from the collector of the other.When power is applied, suppose Q1 turns on a few nanoseconds faster than Q2.
Metal Detector Schematic
- Simple Metal Detector - Theory and schematic provided by HobbyHour
- Balance Metal Detector - Each coil modifies the frequency of the adjacent oscillator through mutual coupling
- Simple Metal Detector - Used one 40106 hex Schmitt inverter IC, a capacitor and a search coil
- Metal Detector-1 - A fun metal detector to find coins at the beach
- One Coil Induction Metal Detector - Offered induction type metal detector is all-purpose
- Coil Coupled Operation Metal Detector - made from readily obtainable component
Thursday, December 11, 2014
Adjustable Lab Power Supply
Make your own lab power supply complete with adjustable voltage and constant current source. Using single IC (LM324)
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