nº975

 

Four stages fading sequencer. Two transistors per stage, supply +5V_USB.

nº974

 

Transistor phase-shift oscillator with 4 stages.(45º)

nº973

 

Self-quenching general purpose timer NE555N, supply +5V_USB

nº972

 

Self-quenching the simple 1 transistor RC phase-shift oscillator, supply 3xNiMH

nº971

 

The modified RF colpitts oscillator / The ultra audion oscillator.

nº970

 

Minimalist mains supplied led sequencer. Synchronization is achieved by using neon lamp. Only low voltage transistors are used.

nº969

 

Simple led ring oscillator, supply 230Vac/50Hz

nº968

 

Experimental VHF super-regenerative receiver compatible with airband. Two transistors. Super-regenerative detector based on 2SC2786. Earphones cable performs also as VHF antenna. Supply 3xR03.

nº967

 

Simple heads or tails game with 2 transistors; slow decay; supply 2xLR03.

nº966

 

Simple electronic game: the cross of fortune; probability that the crossing red-green led turns on is 4/100, supply 2xLR03.

nº965

 

Siren with 3 transistors, supply 12V

nº964

 

Simple whistling detector based on LM567, supply 6V

nº963

 

Simple alarm triggered by interrupting wire loop. 7 pcba components( 3 transistors + 2 resistors + 2 capacitors). Standby current consumption less than 1uA; supply 12V( 8xAA or AAA)

nº962

 

"Knight rider" led sequencer with 10 red leds driven by 1 transistor; supply 12V

nº961

 

1 led voltmeter(0-10V). The number of led flashes is the same as the number of  volts present at circuit input. After counting cycle the led turns off longer and the counting cycle is restarted; supply 12V.

nº960

 

White led luminous intensity controlled by single tact-switch. Up/Down loop variation discrete or continuous. Uses only one LM324 Quad opamp integrated circuit, supply 5V.

nº959

 

Simple RC low pass filter for measuring stand-by DC current consumption of devices having pulsed currents. Time constant adjustable from 0.6s to 30s.

nº958

 

Minimalist MW experimental regenerative radio receiver. Only ferrite rod antenna; 1 transistor; audio output with 32+32ohm common earphones; no tickler coil; supply 2xNiMH. Can satisfactory  tune during daylight to AM broadcast station disted about 30Km from 50kW transmitter. 

nº957

 

Super-regen radio receiver for the FM band with audio amplifier KA2212, supply 5V

nº956

 

Experimental short range RF doorbell for FM radio receiver. Two transistors, 40cm wire antenna, supply 9V