Miscellaneous electronic circuits

This simple counter can be used to count pulses... [read]

This circuit provides a delayed visual indication when a door bell switch is pressed. Very helpful for deaf people.... [read]

You can play this game alone or with your friends. The circuit comprises a timer IC, two decade counters and a display driver along with a 7-segment display.... [read]

This circuit produces a sound similar to a factory siren. It makes use of a 555 timer Ic used as an astable multivibrator of a center frequency of about 300Hz.... [read]

A very high quality intercom, which may also be used for room monitoring... [read]

High Voltage Stun Gun. It's not a toy!... [read]

22kHz oscillator which produces sound that should repel insect. It has adjustable frequency. Its built around one CMOS 4047 circuit. ... [read]

Don't like your little brother's TV channel selection? Hate the volume your wife sets the stereo at? Want to just annoy someone? This circuit does all that... [read]

This jam circuit can be used in quiz contests wherein any par- ticipant who presses his button (switch) before the other contestants, gets the first chance... [read]

Imagine that is morning , you barely anticipate the bus for work and you can't find your keys. If you suffer from this situation frequently, this circuit is... [read]

This is circuit diagram of an interesting toy. It lights up if You move "magic wand" over it in the precisely right way that only you know!... [read]

This little gun can propel a small slug about 1.5 meters high, or 2.5 meters horizontally. It produces magnetic field using four coils and 4017b and NE555... [read]

This is a small, portable set, designed for those aiming at look improvement. The Bio-Stimulator provides muscles' stimulation and invigoration but, mainly,... [read]

This is a small, portable set, designed for those aiming at look improvement. The Bio-Stimulator provides muscles' stimulation and invigoration but, mainly,... [read]

This circuit proved very useful in keeping away from a terrace or a porch some bats and other nocturnal animals. You can use it for similar or different purposes.... [read]

A programmable code lock can be used for numerous applications in which access to an article/gadget is to be restricted to a limited number of persons. Here... [read]

Light emitting diodes are advantageous due to their smaller size, low current consumption and catchy colors they emit. Here is a running message display circuit... [read]

Many people experienced sleeping well in natural surroundings, into a tent or a wooden hut. This fact is due not only to the healthy atmosphere but also from... [read]

This circuit uses a UM3561 IC to produce four different sound effects... [read]

Just point this small device at the TV and the remote gets jammed.... [read]

One more circuit with famous NE555 timer circuit. This one produces ultrasound which can be heard by many animals. It's built to be "loud".... [read]

It is well know that pests like rats, mice etc are repelled by ultrasonic frequency in the range of 30 kHz to 50 kHz. Human beings can�t hear these high-frequency... [read]

This circuit uses an LM11 to form a voltage follower with 1G ohm input resistance built using standard resistor values.... [read]

This device beeps intermittently for approx. two seconds when a person in a range of about 10 meters emits a whistle.... [read]

Beeps when hears your whistle. A gadget suitable for key-holders, games etc. ... [read]