nº955

 

Simple regenerative AM receiver for the MW band: 1 darlington transistor / loudspeaker volume / requires extra 1,5mts wire antenna / no tickler coil ( the ferrite rod antenna assy has impedance matching coil, however it is not used in this case) / no earth connection / supply 5V or  9V.

nº954

 

Prototype of clap lamp switch for lamps having E27 holder, supply 230Vac/50Hz

nº953

 

Experimental TRF regenerative MW receiver with 1 transistor; audio output by piezoelectric speaker, 10mts wire antenna + PE connection, supply 9V.

nº952

 

Simple MW reflex radio using audio amplifier KA2212, supply 9V

nº951

 

Simple MW reflex radio based on audio amplifier TDA1013B, supply 12V

nº950

Audio amplifier driving piezoelectric loudspeaker is turned on and off by knocking on the piezoelectric loudspeaker, supply 12V

nº949

Doorbell with piezoelectric loudspeaker which has two functions: doorbell button and tone reproduction, supply 12V

nº948

Sinewave led sequence with memory effect, supply 9V

nº947

Led triangle with line-by-line filling is controlled by 1 bipolar transistor, supply 9V

nº946

Ear replacement for in-ear earphones tester, supply 2xNiMH

nº945

Simple "joules thief" driving RGB led with 1 bipolar transistor has 6 operating modes: permanent R, G, B or blinking R, G, B; supply 1xNiMH.

nº944

Audio link with decorative mini incandescent lamp

nº943

Simple bargraph with dual red-green leds, supply 24V

nº942

The emitter coupled astable multivibrator

nº941

Overlap of two led sequences with 5 dual red-green leds, supply 12V

nº940

Minimalist reflex radio receiver for MW band; only ferrite antenna, no earth connection, no variable capacitor; tuning by variable inductor; 2 bipolar transistors; loudspeaker output, supply 1xNiMH

nº939

Mains power failure alarm with 2 transistors; stand-by current drawn from LR03 battery is less than 100uA

nº938

Simple SCR random led sequencer with 5 white leds, supply 24V

nº937

Knight rider led effect with 20 leds, 1 BC transistor, supply 24V

nº936

8 leds, 1 bipolar transistor, supply 9V

nº935

Simple led chaser with progressive shortening, supply 2xNiMH

nº934

Simple QC2.0 - 12V mode tester for USB charger. Checks if USB charger is true QC2.0

nº933

Precise refrigerator temperature alarm. When internal temperature exceeds preset value between 0 and 10 degrees Celsius a powerfull alarm signal is triggered. It can be heard even with door closed. Low current consumption in stand-by, Supply 4xNiMH

nº932

Simple "red led catch game" with adjustable speed, supply 2xNiMH

nº931

SW band to MW band frequency converter with 1 transistor, supply 4xNiMH.

nº930

Ganged variable capacitor with reading scale

nº929

Simple lamp flasher controlled by LDR, supply +5V_USB

nº928

Four levels clapper for incandescent lamp; low sensitivity to speech, high sensitivity to clapping, supply 230Vac/50Hz.

nº927

Dimmer for incandescent lamp with 4 levels: OFF, L_min, L_med, L_max; tact-switch operates with total galvanic isolation, supply 230Vac/50Hz.

nº926

Staircase lamp controlled by smartphone ringtone. The ringtone audio signal derived from earphones output activates staircase lamp for the predefined timing. Complete galvanic isolation between TRS plug and circuit hot side is achieved by: 1) using one optocoupler to trigger monostable circuit and 2) A photovoltaic led coupler consisting on the hot side white led voltage regulator coupled to yellow led which supplies energy to the optocoupler audio trigger amplifier.

nº925

Light controlled audio spectral glider, supply 3V

nº924

Audio effect "wah wah", suppy 3V

nº923

Longwave experimental radio receiver with 2 bipolar transistors and loudspeaker output. Operating by night, tuning at 252kHz, Radio Algérie, Chaîne 3, supply 3V

nº922

Two RC resonant active filters select two frequencies: 910Hz and 2KHz.

nº921

Inductance meter 47uH-10mH; reading 1uH/ohm, supply 3V

nº920

Staircase timer opto-switch with about 18 seconds fixed timing, supply 230Vac/50Hz

nº919

Experimental SW(9MHz) regenerative receiver: 2 transistors, tickler coil, tuning capacitor, reaction capacitor, loudspeaker output, supply 9V

nº918

Emitter follower RC phase-shift oscillator

nº917

Beep beep mini alarm with led and 1 bipolar transistor supplied with 1 NiMH battery cell: the audio "joules thief"

nº916

Powerful alarm with 2 bipolar transistors is activated by separating small magnet from oscillator inducance, supply 2xLR03

nº915

Simple portable minimalist reflex radio receiver for MW with 2 bipolar transistors, only tuning control, loudspeaker output, supply 1,5V (1xLR03)

nº914

Led chaser with 18 yellow leds is controlled by single CD4017, 10 states counter, supply 3V

nº913

Simple Colpitts oscillator with MOSFET

nº912

MOSFET phase-lag oscillator