Bike speedometer (CB20497E)

This circuit can be powered by a solar cell. The circuit is from a 1991 documentation having a phototransistor as sensor.

4093 Programmable Active Cycle Lamp Flasher (CB13186E)
The circuit in the figure causes an incandescent lamp to flash at a speed determined by the...
Gain 10 CA3140 Amplifier (CB15503E)
The voltage gain of the circuit shown in the figure is 10 times. This gain is given by the ratio...
Turntable preamplifier II (CB19173E)
This preamp version uses BC109 transistors that are older versions of the current BC549 in plastic...