This circuit was found in a 1969 Mullard documentation. Used transistors can be replaced with modern equivalents. Output transistors may be BD135 and 136 with heatsinks.
This VCO makes use of components from the 1980s. The circuit can be implemented with modern...
This circuit uses an LDR as a sensor to trigger an LED indicator at a preset lighting level. The...
This circuit was found in a 1968 General Electric documentation. It has an input impedance of 2 M ohms...