Active FM Booster

This is a simple low cost circuit of an active FM booster that can be used to amplify the FM band signal, so you can listen the FM channels/programs from distant FM stations clearly. The circuit make use of a common-emitter tuned RF preamplifier wired around VHF/UHF transistor 2SC2570. (Only C2570 is annotated on the… Read More »

Simple Electronic Muscular Stimulator

Here’s a circuit which stimulates nerves of the part of your body exactly where electrodes are generally attached. It is useful to help remedy headache along with muscular discomfort and bring back frozen muscles that impair movement. Though it offers muscles stimulation and invigoration, it”s mostly an aid in removing cellulitis. The device comprises 2… Read More »

Telephone Ringtone Generator

This is really a very simple home telephone ring tone generator circuit which is built with applying only several electronic components / parts. It generates simulated telephone ring tone and requires only DC supply with 4.5V DC to 12V DC voltage. One may possibly use this circuit in ordinary intercom or phone-type intercom. The sound… Read More »

Pyroelectric Fire Alarm System

This is definitely an ultra-sensitive fire sensor that exploits the direct piezoelectric property of an ordinary piezo component to recognize the fire. The lead zirconate titanate crystals within the piezo component have the property to deform and produce an electrical potential when heated, thus converting the piezo component into a heat sensor. The circuit mentioned… Read More »

4 Stage FM Transmitter

This is the FM transmitter circuit which apply 4 radio frequency stages, that are a VHF oscillator designed around transistor BF494 (T1), a preamplifier designed around transistor BF200 (T2), a driver designed around transistor 2N2219 (T3) and also a power amplifier designed around transistor 2N3866 (T4). A condenser microphone is wired at the input of… Read More »